The concept of vulnerability in aged care: a systematic review of argument-based ethics literature. — TEI-tagged view

Virginia SanchinipersName, Roberta SalapersName, Chris GastmanspersName (2022date). “The concept of vulnerability in aged care: a systematic review of argument-based ethics literature..” BMC Medical Ethicstitle·j.

Object of study — argument-based ethics literature on vulnerabilityterm·dom in aged careterm·key

Research question — what vulnerabilityterm·dom means in the ethics literature on aged careterm·key

Contribution — a systematisation of the conceptions of older adultsterm·key' vulnerabilityterm·dom: basic human and situational, six dimensions, three ways of responding

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The concept of vulnerabilityterm·dom in aged careterm·key: a systematic reviewterm·mth of argument-based ethics literature.

Abstract Vulnerabilityterm·dom is a key concept in traditional and contemporary bioethicsterm·key. In the philosophical literature, vulnerabilityterm·dom is understood not only to be an ontological condition of humanity, but also to be a consequence of contingent factors. Within bioethicsterm·key debates, vulnerable populationsterm·dom are defined in relation to compromised capacity to consent, increased susceptibility to harm, and/or exploitation. Although vulnerabilityterm·dom has historically been associated with older adultsterm·key, to date, no comprehensive or systematic work exists on the meaning of their vulnerabilityterm·dom. To fill this gap, we analysed the literature on aged careterm·key for the meaning, foundations, and uses of vulnerabilityterm·dom as an ethical concept.

Using PRISMA guidelines, we conducted a systematic reviewterm·mth of argument-based ethics literature in four major databases: PubMed, Embase®, Web of Science™, and Philosopher’s Index. These covered biomedical, philosophy, bioethical, and anthropological literature. Titles, abstracts, and full texts of identified papers were screened for relevance. The snowball technique and citation tracking were used to identify relevant publications. Data analysis and synthesis followed the preparatory steps of the coding process detailed in the QUAGOLterm methodology.

Thirty-eight publications met our criteria and were included. Publication dates ranged from 1984 to 2020, with 17 publications appearing between 2015 and 2020. Publications originated from all five major continents, as indicated by the affiliation of the first author. Our analyses revealed that the concept of vulnerabilityterm·dom could be distinguished in terms of basic human and situational vulnerabilityterm·dom. Six dimensions of older adultsterm·key’ vulnerabilityterm·dom were identified: physical; psychological; relational/interpersonal; moral; sociocultural, political, and economic; and existential/spiritual. This analysis suggested three ways to relate to older adultsterm·key’ vulnerabilityterm·dom: understanding older adultsterm·key’ vulnerabilityterm·dom, taking care of vulnerable older adultsterm·key, and intervening through socio-political-economic measures.

The way in which vulnerabilityterm·dom was conceptualised in the included publications overlaps with distinctions used within contemporary bioethicsterm·key literature. Dimensions of aged careterm·key vulnerabilityterm·dom map onto defining features of humans, giving weight to the claim that vulnerabilityterm·dom represents an inherent characteristic of humans. Vulnerabilityterm·dom is mostly a value-laden concept, endowed with positive and negative connotations. Most publications focused on and promoted aged careterm·key, strengthening the idea that care is a defining practice of being human.

The online version contains supplementary material available at 10.1186/s12910-022-00819-3.

Background The word ‘vulnerabilityterm·dom’ derives from the Latin verb vulnerare (i.e., wounding) and from the Latin noun vulnus (i.e., wound). Therefore, etymologically, vulnerabilityterm·dom mostly refers to the susceptibility of being physically or emotionally wounded [ 1 , 2 ]. Yet, besides this prima facie characterisation, the notion of vulnerabilityterm·dom has eschewed a univocal definition, both within and across distinct threads of the literature [ 1 , 3 – 5 ].

In philosophical literature, vulnerabilityterm·dom is mostly considered to be a defining ontological feature of human beings, who are exposed to finitude and subject to the consequences of human embodiment, including the mutual interdependence and/or sociality that inherently structure human life [ 6 – 9 ]. Complementary— or, in some cases, alternative—philosophical approaches have interpreted vulnerabilityterm·dom as the consequence of contingent factors, which expose some beings more than others to the aforementioned ‘wounds’, rather than interpreting it as a universal trait of our humanity [ 10 , 11 ].

In debates within mainstream bioethicsterm·key, vulnerabilityterm·dom is mostly addressed in terms of vulnerable populationsterm·dom, thus shifting the focus from theoretical concepts to groups of individuals. However, defining vulnerable populationsterm·dom or groups has also proved difficult [ 3 ], while the concept of vulnerabilityterm·dom itself remains ill-defined in such literature. In broad terms, the label ‘vulnerable’ has been attributed to populations characterised by compromised capacity for consent (e.g., patients with serious cognitive impairments); by being at a higher risk of incurring in harm and/or wrongs (e.g., pregnant woman); or by both (e.g., children belonging to certain ethnic groups). Moreover, within research ethics policy and guidelines, vulnerable populationsterm·dom have been defined in relation to ‘reasons for vulnerabilityterm·dom’ [ 12 ], which can be divided into two broad groups—‘respect for persons-based accounts’ and ‘justice-based accounts’ [ 12 p. 2]. According to ‘respect for persons-based accounts’, ‘persons who cannot provide informed and voluntary consent are susceptible to harm (i.e., vulnerable), because they are not able to protect their interests’ [ 12 p. 2]. According to ‘justice-based accounts’, vulnerable populationsterm·dom are those that are potentially more exposed to unfairness during recruitment and distribution of research benefits and risks, as well to exploitation, broadly understood. In addition, overlap between reasons for vulnerabilityterm·dom, and hence of categories of vulnerable individuals, may occur. According to these interpretations, vulnerabilityterm·dom has a negative connotation, and thus requires some form of intervention, among which ‘extra justification for including vulnerable populationsterm·dom in research’ [ 13 , 14 ], ‘considered’/‘special’ protection [ 15 , 16 ], and research and healthcare tailored on vulnerable populationsterm·dom’ needs [ 15 – 17 ] are paramount.

Historically, among the categories of vulnerable people, older persons are predominant. Older adultsterm·key represent a vulnerable populationterm·dom in public health ethics [ 18 – 21 ], research ethics [ 16 , 17 ], and clinical ethics domains [ 22 – 24 ]. From a pathophysiological perspective in clinical ethics, an older adultterm·key is someone who is in a state of constant cognitive and physical decline [ 25 ]. Moreover, this condition leads to progressive depletion of functional reserve mechanisms, reduced homeostatic capabilities, and is frequently accompanied by complex comorbidities, which are often further complicated by geriatric syndromes and frailtyterm·key [ 25 ]. From a psychosocial standpoint, ageing represents a life state characterised by contrasting requests (e.g., protection vis-a-vis autonomy recognition). Moreover, conditions such as income insecurity, lack of access to quality healthcare, unfriendly environments, and psychodynamic factors (e.g., uncertain future and fear of death) may further worsen older adultsterm·key’ stability and increase their vulnerabilityterm·dom. Finally, loneliness, and, in some circumstances, even isolation, may also characterise old age: Many elderly persons live alone, may be widowers, who often live in nursing homes. At the same time, some of their peers remain in their own homes, accompanied by caregivers who become their sole companions [ 26 – 29 ].

Although all these conditions may be thought of as being equivalent to older adultsterm·key’ vulnerabilityterm·dom, no comprehensive or systematic research on vulnerabilityterm·dom in older adultsterm·key has appeared in the literature. As a group, older adultsterm·key are mostly assumed a priori to be or referred to as being vulnerable in bioethicsterm·key and research ethics. In some but still limited cases, scholars have proposed different (even incompatible) conceptualisations of vulnerabilityterm·dom in the wider bioethicsterm·key literature that potentially seem to hold relevance for geriatric care. This systematic reviewterm·mth provides an overview of these different conceptualisations of vulnerabilityterm·dom and discusses their moral relevance, value, and the way that acknowledgments of vulnerabilityterm·dom are thought to create obligations of care in the context of geriatric care. The findings of the reviewterm·mth will facilitate further philosophical and bioethical research on arriving at a more context-specific and robust conceptualisation of vulnerabilityterm·dom in the domain of geriatric care.

Methodology To gain a comprehensive overview of the definitions, meanings, and the way that authors use the concept of vulnerabilityterm·dom in aged careterm·key, we conducted a systematic reviewterm·mth of argument-based literature [ 30 , 31 ]. Argument-based reviewsterm are important for acquiring evidence for better decision-making in the delivery of healthcare, policy development, and conducting medical research [ 30 , 32 ]. They consist of a curation and evaluation of normative bioethicsterm·key literature aimed at answering an ethical question.

Research questions We formulated the following interrelated groups of research questions: What is the meaning of vulnerabilityterm·dom in the ethics literature on aged careterm·key? In this context, does vulnerabilityterm·dom differ from other similar concepts, such as fragility, frailtyterm·key, and frailness? What are the ethical arguments and approaches used for discussing vulnerabilityterm·dom in aged careterm·key ethics? What are the obligations, if any, that follow from the acknowledgment of older adultsterm·key' vulnerabilityterm·dom as reported in the aged careterm·key literature?

Literature search The four research questions were formulated according to three groups of concepts we devised to organise our literature search (Table 1 ). Table 1 Groups of organising concepts for searching the literature and their associated database search terms Group 1: vulnerabilityterm·dom Group 2: target population Group 3: ethics Vulnerabilityterm·dom; vulnerable; fragility; frailtyterm·key; frail; frailness Dementia; aged; aging; ageing; elder; elderly; older people; older adultterm·key; old people Ethics; philosophy; bioethicsterm·key; anthropology; medical anthropology These ‘structures’ progressively culled publications to those that allowed us to answer our research question. The purpose of Group 1 concepts was to identify publications that focused on the concept of vulnerabilityterm·dom and/or akin concepts, e.g., fragility. The purpose of Group 2 was to help narrow down papers that dealt with the specific population under investigation, i.e., older adultsterm·key. The purpose of Group 3 was to restrict the search to research domains that likely contained papers using conceptualisations of vulnerabilityterm·dom and/or akin concepts. Each group concept was expressed in specific database search terms in a suitable format for the different database queries (Table 2 ). Research strings were developed by the first author (VS) in consultation with the last author (CG). Table 2 Search strings used for searching databases stratified by organising concepts* Database Group 1: vulnerabilityterm·dom Group 2: target population Group 3: ethics Pubmed ((((((((((vulnerabilityterm·dom[Title/Abstract]) OR vulnerab*[Title/Abstract]) OR fragility[Title/Abstract]) OR frailtyterm·key[Title/Abstract]) OR frail[Title/Abstract]) OR fragilit*[Title/Abstract]) OR frailness[Title/Abstract]) OR frailties[Title/Abstract])) OR "Frailtyterm·key"[Mesh])) AND ((((("Dementia"[Mesh:NoExp] OR dementia [Title/Abstract])) OR ((((((((((aged[Title/Abstract]) OR aging[Title/Abstract]) OR ageing) OR elder*) OR elderly) OR older people) OR older adultterm·key*) OR old people)) OR "Aging"[Mesh:NoExp]) OR (("Aged"[Mesh]))))) AND (((("Ethics"[Mesh] OR "Philosophy"[Mesh] OR ethic* OR philosophy OR bioethicterm·key*[Title/Abstract] OR philosophical[Title/Abstract] OR moral[Title/Abstract] OR morals[Title/Abstract]))) OR ("Anthropology, Medical"[Mesh] OR "anthropologic*" [Title/Abstract])) Embase vulnerabilityterm·dom:ti,ab,kw OR vulnerab*:ti,ab,kw OR fragility:ti,ab,kw OR fragilit*:ti,ab,kw OR frailtyterm·key:ti,ab,kw OR frailties:ti,ab,kw OR frailness:ti,ab,kw AND 'aged'/de OR 'aged hospital patient'/de OR 'frail elderly'/exp OR 'institutionalized elderly'/exp OR 'very elderly'/exp OR 'aging'/de OR 'dementia'/de OR aged:ti,ab,kw OR ageing:ti,ab,kw OR elder*:ti,ab,kw OR elderly:ti,ab,kw OR 'older people':ti,ab,kw OR 'old people':ti,ab,kw OR 'older adultsterm·key':ti,ab,kw OR dementia:ti,ab,kw AND 'medical anthropology'/exp OR anthropologic* OR 'ethics'/exp OR 'philosophy'/exp OR 'ethics':ab,ti,kw OR 'ethical':ab,ti,kw OR 'philosophy':ab,ti,kw OR 'philosophical':ab,ti,kw OR 'bioethicsterm·key':ab,ti,kw OR 'bioethical':ab,ti,kw OR 'moral':ab,ti,kw OR 'morals':ab,ti,kw Web of Science TS = (vulnerabilityterm·dom OR vulnerab* OR fragility OR frailtyterm·key OR fragilit* OR frailness OR frailties) AND TS = (aged OR aging OR ageing OR elder* OR elderly OR older people OR old people OR older adultterm·key* OR dementia) AND TS = (ethics OR ethical OR philosophy OR philosophical OR bioethicsterm·key OR bioethical OR moral OR morals OR medical anthropology) Philosopher’s Index noft(vulnerabilityterm·dom OR vulnerable OR vulnerab* OR fragility OR frailtyterm·key OR fragilit* OR frailness OR frailties) AND noft(aged OR aging OR ageing OR elder* OR elderly OR older people OR old people OR older adultterm·key* OR dementia) AND noft(ethics OR ethical OR philosophy OR bioethicsterm·key OR bioethical OR moral OR morals OR medical anthropology) *See Table 1 for organising concepts Four major databases were queried: Pubmed®, Embase®, Web of Science™, and Philosopher’s Index. These databases, as a group, cover the literature in biomedicine, bioethicsterm·key, philosophy, and (medical) anthropology.

Database queries were conducted between the 19th and the 23rd of December 2019, using language filters to identify only articles published in English (Table 3 ). Table 3 presents the number of results returned using the search terms, as well as the specific days on which the searches were performed. Table 3 Literature search results (‘hits’) for each database and English-only results Database Search date Number of results Results (English-only filter) Pubmed 19/12/2019 3758 3498 Embase 23/12/2019 1368 1290 Web of science 21/12/2019 989 898 Philosopher’s index 23/12/2019 51 49 Total 6166 5735 We used EndNote™ (version X9, Clarivate Analytics, Philadelphia, PA, USA) reference library software to conduct and organise citations of the identified papers; duplicates were manually deleted.

The first author (VS) screened the titles, abstracts, and full texts of identified papers, according to a predefined set of inclusion and exclusion criteria (below) [ 33 ]. Abstract screening was performed independently by the first (VS) and last (CG) authors to assess the consistency of applying our selection criteria. For 91.94% of the abstracts (559 of 608), we agreed on the items to be included or excluded. For the questionable abstracts (8.06%, corresponding to 49 papers), the first (VS) and last (CG) authors discussed the candidate abstract until agreement was reached. If the full text of an article was not available, we emailed the first or corresponding author of that article to request a PDF copy. We also used the snowball technique and citation tracking to identify additional potentially relevant publications. Our search process was performed according to the statement and flowchart of the Preferred Reporting Items for Systematic Reviewsterm·mth and Meta-Analysis (PRISMA) [ 33 ] (Fig. 1 ). Fig. 1 Prisma scheme Flow chart showing electronic database search, publication identification, and selection process for the included articles The final list of included publications is reported in Table 4 . The description of characteristics of included publications is reported in Table 5 . Table 4 List of included publications and summary descriptions ( N = 38) No.* Author Country affiliation of first author Publication year Professional background of first author Study focus 38 Agu Francis C Africa 2013 Bioethicsterm·key Vulnerabilityterm·dom 39 Baars Jan The Netherlands 2013 Philosophy Vulnerabilityterm·dom 40 As above As above 2017 As above Vulnerabilityterm·dom 41 Blasimme Alessandro Switzerland 2017 Philosophy Frailtyterm·key 42 Bozzaro Claudia Germany 2018 Philosophy Vulnerabilityterm·dom 43 Brocklehurst Hilary United Kingdom 2008 International relations Vulnerabilityterm·dom 44 Brown Ivan Canada 1995 Psychology Frailtyterm·key 45 Casey Marie S Australia 1995 Nursing Vulnerabilityterm·dom 46 Denny Dawn L USA 2012 Nursing Vulnerabilityterm·dom 47 Dunn Michael United Kingdom 2018 Bioethicsterm·key Vulnerabilityterm·dom 48 Erlen Judith Ann USA 2007 Nursing Vulnerabilityterm·dom 49 Gadow Sally USA 1983 Nursing, Philosophy Frailtyterm·key 50 Groenhaut Ruth USA 2019 Philosophy Frailtyterm·key and Fragility 51 Grundy Emily United Kingdom 2006 Medical Demography Vulnerabilityterm·dom 52 Hardin Sonya R USA 2015 Nursing Vulnerabilityterm·dom 53 Hoffmaster Barry Canada 2006 Philosophy Vulnerabilityterm·dom 54 Jecker Nancy S USA 1991 Philosophy Vulnerabilityterm·dom 55 Jena Yeremias Indonesia 2014 Philosophy; Bioethicsterm·key Vulnerabilityterm·dom 56 Kaufman Sharon R USA 1994 Medical Anthropology Frailtyterm·key 57 Körtner Tobias Austria 2016 Psychology Vulnerabilityterm·dom 58 Laceulle Hanne The Netherlands 2017 Philosophy Vulnerabilityterm·dom 59 As above As above 2018 As above Vulnerabilityterm·dom 60 Lloyd-Sherlock Peter United Kingdom 2006 Geography; Economics Vulnerabilityterm·dom 61 Luna Florencia Argentina 2014 Philosophy; Bioethicsterm·key Vulnerabilityterm·dom 62 Makela Petra United Kingdom 2018 Medical doctor Frailtyterm·key 63 Morell Carolyn M USA 2003 Social Science Vulnerabilityterm·dom and Frailtyterm·key 64 Niemeyer-Guimaraes Marcio Brazil 2017 Medical doctor Vulnerabilityterm·dom 65 O’ Brolchain Fiachra Ireland 2019 Philosophy Vulnerabilityterm·dom 66 Pickard Susan United Kingdom 2019 Sociology Frailtyterm·key 67 Raphael Dennis USA 1995 Psychology Frailtyterm·key 68 Raudonis Barbara M USA 2010 Nursing Frailtyterm·key 69 Rook Karen S USA 2017 Psychology Vulnerabilityterm·dom 70 Schröder-Butterfill Elisabeth United Kingdom 2006 Human Sciences; Gerontology Vulnerabilityterm·dom 71 Siegler Mark USA 1984 Medical doctor Vulnerabilityterm·dom 72 van der Meide Hanneke The Netherlands 2015 (Cultural) Anthropology; Philosophy Vulnerabilityterm·dom 73 Van Eeuwijk Peter Switzerland 2006 (Social) Anthropology Vulnerabilityterm·dom 74 Waldon Mandy United Kingdom 2018 Nursing Frailtyterm·key 75 Wareham Christopher Simon Africa 2015 Bioethicsterm·key Vulnerabilityterm·dom * Publication identification number Table 5 Detailed characteristics of included publications ( N = 38) Analysed features (Number of Publications)/Paper No. as listed in Table 4 1. Focus Vulnerabilityterm·dom (27): 38–40, 42, 43, 45–48, 51–55, 57–61, 64, 65, 69–73, 75 Frailtyterm·key (9): 41, 44, 49, 56, 62, 66–68, 74 (both) Frailtyterm·key and fragility (1): 50 (both) Vulnerabilityterm·dom and frailtyterm·key (1): 63 2. Country affiliation of the first author Americas (16): Argentina (1): 61; Brazil (1): 64; Canada (2): 44, 53; USA (12): 46, 48, 49, 50, 52, 54, 56, 63, 67, 68, 69, 71 Europe (18): Austria (1): 57; Germany (1): 42; Ireland (1): 65; Switzerland (2): 41, 73; The Netherlands (5): 39, 40, 58, 59, 72; United Kingdom (8): 43, 47, 51, 60, 62, 66, 70, 74 Africa (2): 38, 75 Australia (1): 45 Indonesia (1): 55 3. Year of publication 2020–2015 (17): 40–42, 47, 50, 52, 57–59, 62, 64–66, 69, 72, 74, 75 2014–2010 (6): 38, 39, 46, 55, 61, 68 2009–2005 (7): 43, 48, 51, 53, 60, 70, 73 2004–2000 (1): 63 Before 2000 (7): 44, 45, 49, 54, 56, 67, 71 4. Population under investigation Older adultsterm·key, no specified age and/or gender (22): 39, 40, 42–45, 47, 49–51, 53, 56–59, 66–71, 74, 75 Older adultsterm·key, specified age (4): 38 & 41 (+ 65-years-old), 46 (70 and above), 48 (80 and above) Older adultsterm·key in ‘upper middle’ income countries (according to the country list, World Bank) (5): 55, 70, 73 (Indonesia), 60 (Thailand); 61 (Brazil & Argentina) Female older adultsterm·key (2): 54, 63 Hospitalised older adultsterm·key (2): 52, 72 Older adultsterm·key with dementia (1): 65 Residents of nursing homes (1): 62 Cancer, older patients (1): 64 5. Main ethical approach* (21) Phenomenology and existentialism (5): 42, 45, 49, 66, 72 Care Ethicsterm·dom (4): 48, 50, 56, 72 Feminist Ethics (4): 50, 54, 62, 63 Principlismterm·dom (3): 38, 46, 57 Capability Approachterm·dom (2): 41, 47 Public Health Ethics (2): 61, 67 Virtue Ethics (2): 58, 65 Analytic political philosophy (1): 75 Personalistic Ethicsterm·dom (1): 55 Articles that do not explicitly refer to a specific ethical theory or approach (17): 39, 40, 43, 44, 51–53, 59, 60, 64, 68–71, 73, 74 *A single article can be represented more than once Inclusion and exclusion criteria To be included in our systematic reviewterm·mth and appraisal, candidate publications had to meet all inclusion criteria and had to have no exclusionary ones (Table 6 ). Screening of the publications was not limited by publication date. Table 6 Inclusion and exclusion criteria for selection of the articles Criteria Inclusion Exclusion Topic Significant use of the concept of vulnerabilityterm·dom and/or related concepts (i.e., frailtyterm·key, frailness, fragility) Use of the concept of vulnerabilityterm·dom and/or akin concepts was not significant, and/or it was used in a purely medical sense Research domain Application to the specific field of aged careterm·key (broadly understood) Reference to fields other than aged careterm·key (e.g., research ethics) Population Reference to older adultsterm·key Target population is not represented by older adultsterm·key Language Publication must be in English Publications in languages other than English Types Publication is considered to be in the argument-based literature; i.e., an article using ethical concepts derived from current or traditional ethical theories in order to argue for a position or conclusion Editorials, book chapters, position papers, guidelines, reviewsterm·mth, protocols, ethics policies, and ethics codes As there is no standard for quality appraisal of papers in the argument-based literature, we referred to the ‘appraisal using procedural quality assurance criteria’s strategy’ of Mertz [ 31 ]. Quality appraisal was not used as a tool for inclusion/exclusion. Since the articles were published in peer-reviewed journals, we relied on the standards of the peer reviewterm·mth process and on the academic reputation of the journals to bolster our assumptions that the quality of selected publications was sufficiently good.

Data extraction and synthesis Data analysis and synthesis adhered to the five preparatory steps of the coding process detailed in the Qualitative Analysis Guide of Leuven (QUAGOLterm) [ 34 , 35 ]. QUAGOLterm has been used in other argument-based reviewsterm [ 32 , 36 , 37 ].

For data extraction, the first author (VS) first read and reread several times all the included publications, highlighting the relevant parts and the main arguments described. The same author then developed a narrative summary of these highlighted parts. Third, for each publication, a conceptual schemeterm was created. The conceptual schemeterm is a synthetic framework in which different concepts deemed relevant to answer the research questions are presented [ 34 , 35 ]. An example of a conceptual schemeterm is presented in Additional file 1 : “Example of conceptual schemeterm”. Each conceptual schemeterm was analysed separately by the first (VS) and last (CG) authors to verify that it accurately characterised each included publication. Both researchers discussed conceptual schemesterm until they agreed on their adequate content. Fourth, these individual conceptual schemesterm were compared, with the aim of uncovering relationships that would produce an overall answer to our research questions. This resulted in a comprehensive scheme that integrated the most relevant meanings and dimensions of vulnerabilityterm·dom and related concepts in aged careterm·key ethics (Tables 7 and 8 ). This scheme was iteratively evaluated and checked against previous QUAGOLterm steps to ensure that it adequately reflected the included papers. Finally, we synthesised a description of these results. Table 7 Global scheme emerging from analysis of the 38 included publications (part one)* Included articles 1. Conceptualisation of vulnerabilityterm·dom (and related concepts), generally understood 1.1 Basic human vulnerabilityterm·dom ( N = 12) Vulnerabilityterm·dom (and related concepts) as an intrinsic trait of human nature 38–40, 42, 49, 50, 53, 55, 58, 59, 64, 65 1.2 Situational vulnerabilityterm·dom ( N = 8) Vulnerabilityterm·dom (and related concepts) as a consequence of extrinsic cultural, social, political, economic factors 41, 44, 51, 52, 55, 61, 66, 68 1.3 NO conceptualisation of vulnerabilityterm·dom, generally understood ( N = 18) 43, 45–48, 54, 56, 57, 60, 62, 63, 67, 69–75 2. Conceptualisation of older adultsterm·key’ vulnerabilityterm·dom (and related concepts) 2.1 Aging as a condition of increased basic human vulnerabilityterm·dom ( N = 9) 38–40, 44, 49, 53, 58, 59, 65 2.2 Aging as a condition of increased situational vulnerabilityterm·dom ( N = 25) 41–43, 46, 47, 48, 51, 52, 54, 56, 57, 60–63, 66–74 2.3 Aging as a condition of both increased basic human & situational vulnerabilityterm·dom ( N = 4) 45, 50, 55, 64 3. Dimensions of aged careterm·key vulnerabilityterm·dom (and related concepts) 3.1 Physical Vulnerabilityterm·dom ( N = 14) Non pathological physical/physiological bodily deterioration related to ageing 43, 44, 48, 50, 52, 53, 54, 61, 62, 67, 68, 70, 74 Pathological physical/physiological conditions related to ageing 43, 50, 52, 61, 65 3.2 Psychological Vulnerabilityterm·dom ( N = 18) Strictly psychological Cognitive 43, 44, 48, 50, 52, 61, 65, 67, 68 Emotional 40, 48, 54, 57, 61, 69, 72 Personal traits 70 Experiential 42, 53, 63, 72 3.3 Relational/interpersonal vulnerabilityterm·dom ( N = 14) Ontological interdependence of the human condition 40, 42, 58, 73 (Inter)dependence in real-world settings 43, 44, 51, 56, 57, 61, 65, 67, 70, 74 3.4 Moral vulnerabilityterm·dom ( N = 7) Positive view 58, 59, 65, 68 Negative view 61, 62, 64 3.5 Socio-cultural, political, and economic vulnerabilityterm·dom ( N = 22) Socio-cultural Broadly understood 41, 50, 51, 55, 68, 70, 73 Isolation/exclusion from social life 42, 43, 45, 62, 65 Marginalisation (also related to racism) 43, 48 Stigmatisation (i.e., ageismterm·dom) 43, 48, 52 Related to gender 54, 73, 74 Low education level attained 70, 74 Political and economic 43, 44, 47, 50, 51, 54, 55, 60, 61, 71, 73, 74, 75 3.6 Existential/spiritual vulnerabilityterm·dom ( N = 15) Trait of human existence 44, 49, 53, 55, 66 Experience of human finitude 38, 42, 55, 58, 66 Acquisition of new meaning(s) 40, 58, 59, 63, 68 Loss of meaning 43, 45, 67, 68 4. Additional conditions/issues correlated to aged careterm·key vulnerabilityterm·dom (and related concepts) 4.1 Depression 43, 44, 68 4.2 Loneliness 45, 54, 66 4.3 Undertreatment of pain 46, 68 .4.4 Medicalisation 56, 62 4.5 Living Situation 44, 52, 61, 62, 67, 70, 72, 74 4.6 Control 56, 65 * A single article can be represented in more than one category Table 8 Global scheme emerging from analysis of the 38 included articles (part two)* Means to address vulnerabilityterm·dom Understanding older adultsterm·key’ vulnerabilityterm·dom (i) Taking care of vulnerable older adultsterm·key (ii) Intervening through socio-cultural, political, and economic measures (iii) Both (i) and (ii) Both (i) and (iii) Ethical approach † Phenomenology and existentialism (42, 45, 49, 66, 72) Principlismterm·dom (38, 46, 57) Capability approachterm·dom (41, 47) Care ethicsterm·dom (48, 50, 56, 72) Personalistic ethicsterm·dom (55) Feminist ethics (50, 54, 62, 63) Virtue ethics (58, 65) Public health ethics (61, 67) Analytic political philosophy (75) *A single article can be represented in more than one category † publication No. as listed in Table 4 Results General description of publications Thirty-eight publications met our inclusion criteria (identified by Nos. 38-75 in Table 4 ). For a detailed description of the general characteristics of the included publications, see Table 5 . All the included publications belong to argument-based literature; thus, they provide conceptual insights on vulnerabilityterm·dom and related concepts (Table 6 ). With respect to the latter, the majority of papers ( N = 27) presented vulnerabilityterm·dom as its object of investigation [ 38 – 64 ]; nine publications referred to frailtyterm·key [ 65 – 73 ]; while two publications focused on both frailtyterm·key and fragility [ 74 ], and vulnerabilityterm·dom and frailtyterm·key, respectively [ 75 ]. Although these are different terms, we considered it acceptable to include publications focusing not only on vulnerabilityterm·dom but also on these other two notions. For these to be included, two conditions had to be met: (i) frailtyterm·key and fragility were used synonymously with vulnerabilityterm·dom; and (ii) they were used within argument-based reasoning and not strictly as medical notions or description.

Publication dates ranged from 1984 to 2020, with 17 articles published between 2015 and 2020 [ 40 , 41 , 45 , 48 , 52 – 54 , 57 – 59 , 62 , 64 , 65 , 69 , 70 , 73 , 74 ]. Studies from the Americas, Europe, Australia-Oceania, Asia, and Africa are represented in this systematic reviewterm·mth; that is, the first author and/or corresponding author was from one of these continents. However, the vast majority of papers came from studies conducted in Europe ( N = 18) and the Americas ( N = 16). Even within Europe and the Americas, the authors’ affiliations varied widely. For authors based in Europe, the authors’ affiliation for 13 of the included publications was from an institution in Britain [ 42 , 45 , 47 , 55 , 60 , 69 , 70 , 73 ] or The Netherlands [ 39 , 40 , 53 , 54 , 62 ]. For authors based in the Americas, the affiliation for 12 of 16 of the included publications was from an institution in the US [ 44 , 46 , 48 , 50 , 59 , 61 , 67 , 68 , 71 , 72 , 74 , 75 ].

To be included in this reviewterm·mth, papers had to have referred to older adultsterm·key in aged careterm·key, that being a broadly understood term. Most papers ( N = 22) referred to the category ‘older adultsterm·key’, without specifying their age, gender or, above all, whether they are affected by a medical condition. Five papers were derived from studies that investigated the condition of older adultsterm·key living in upper-middle income countries [ 51 , 55 , 56 , 60 , 63 ].

While doing data extraction and synthesis, we realised that most authors of the included publications argued from a specific ethical stance in their paper. We identified nine ethical approaches that authors used. The arguments used in two papers were informed by several approaches, and thus their publications were categorised into more than one ethical approach [ 62 , 74 ]. We also identified several ‘outlier’ publications. These are papers that could not be readily categorised into any one of the nine ethical approaches. However, these outliers still clearly dealt with ethical arguments concerning the topic of vulnerabilityterm·dom in aged careterm·key.

Our analysis and synthesis supported a fivefold structure of the included publications (Tables 7 and 8 ). This structure could be conceived of as sections. The first section outlines how the concept of broadly defined vulnerabilityterm·dom was addressed. The second section focuses on vulnerabilityterm·dom in aged careterm·key, thus showing how the different accounts of broadly defined vulnerabilityterm·dom find their counterpart in this narrower debate. Drawing from the adjusted understanding of the first two sections, the third and fourth sections are manifested as a theoretical conceptualisation of vulnerabilityterm·dom in aged careterm·key, explaining in detail its defining dimensions. The fifth section relates the findings concerning the means to address aged careterm·key vulnerabilityterm·dom, with the ethical approaches adopted in the same publications. This showed the relationships between ethical approaches and corresponding strategies for addressing vulnerabilityterm·dom in aged careterm·key.

Conceptualisation of vulnerabilityterm·dom and related concepts: how they are generally understood The majority of papers ( N = 20) engaged in the well-known debate over the definition and conceptualisation of vulnerabilityterm·dom, as it is broadly understood. This debate encompassed the question about what the concept of vulnerabilityterm·dom refers to, in particular, whether it refers to a condition generally affecting human beings as such (namely, what we referred to as ‘basic human vulnerabilityterm·dom’) or whether there are some specific situational conditions that make some human beings more vulnerable than others (namely, what we referred to as ‘situational vulnerabilityterm·dom’) (Table 7 ).

In 12 out of the 20 papers, vulnerabilityterm·dom was defined in terms of basic human vulnerabilityterm·dom. Accordingly, most authors considered vulnerabilityterm·dom to be a normative concept related to the very essence of our anthropological condition [ 41 ] and a necessary attribution intrinsically affecting humankind [ 38 , 39 , 67 , 74 ]; they conceived of this in different ways [ 67 , 74 ]. Thus, for this definition, being vulnerable means first and foremost being exposed to the experience of ‘human finitude’ [ 38 , 39 , 53 , 54 ], which in turn is related to the certainty of death and the ‘fundamental uncertainty’ characterising the human condition [ 40 ]. Basic human vulnerabilityterm·dom means also being open to the possibility of being affected in life by both pleasures and sufferings, as well as experiencing the condition of inter-human dependency [ 40 ]. This latter is also related to the progressive loss of power and/or control that we, as humans, experience during life [ 49 ]. Despite being an innate human trait, basic human vulnerabilityterm·dom does not equally characterise all human beings in the same manner, but it varies depending on the individual subject and/or life conditions a subject is experiencing [ 58 , 67 , 74 ]. In this sense, human vulnerabilityterm·dom can change over time and in the presence of potential stressors related to poor functional decline; this means that it can be repaired or can worsen [ 38 ].

The authors of the remaining eight papers argued for a definition of vulnerabilityterm·dom that is in line with what we term situational vulnerabilityterm·dom. According to this definition, vulnerabilityterm·dom does not refer to a trait characterising human beings as such, but it describes the condition affecting only some agents who are more likely to be harmed and/or injured than others [ 47 , 65 , 66 , 72 ], due to situational contingent circumstances; these can be social, political, or economic [ 51 , 56 ]. This notion of vulnerabilityterm·dom has also a normative connotation, endowed with negative characterisation related to a condition of minority [ 72 ].

The remaining 18 papers were not relevant for this debate about broadly defined vulnerabilityterm·dom; they focused only on the concept of vulnerabilityterm·dom in the context of aged careterm·key.

Conceptualisation of older adultsterm·key’ vulnerabilityterm·dom All the publications included in this systematic reviewterm·mth conceptualised vulnerabilityterm·dom in the context of aged careterm·key. We noticed that older adultsterm·key’ vulnerabilityterm·dom was presented in terms of one of the three possible conditions: (i) increased basic human vulnerabilityterm·dom, (ii) increased situational vulnerabilityterm·dom, (iii) both increased basic human and situational vulnerabilityterm·dom.

Authors discussing ageing in terms of condition (i) ( N = 9) argued that traits representing humans as vulnerable—that is, experiencing finitude, being subject to progressive deterioration, and mutual inter-dependence—are amplified when people become old. Accordingly, our analyses showed that being old primarily means experiencing more intensely the state of human finitude because of a heightened and closer ‘connection with our own mortality’ [ 39 , 40 , 66 ]. Being old also means being subjected to a progressive loss of independence, which appears as being totally compromised in some medical conditions (e.g., dementia); this, in turn, progresses to a greater mutual interdependence [ 58 ].

However, the majority of publications ( N = 25) considered older adultsterm·key’ vulnerabilityterm·dom in terms of condition (ii); that is, vulnerabilityterm·dom is the consequence of one or more situational conditions that may accompany old age. These conditions make older adultsterm·key more ‘exposed’ than other categories of agents to threats or injustices. There may be different kinds of situational conditions, spanning from medical to social, from political to economic conditions, and these more likely result because of their overlap [ 45 , 50 , 55 , 63 ]. In line with this characterisation, older adultsterm·key may be defined as vulnerable, for example, when they are subjected to ageismterm·dom; that is, they are discriminated against in many contexts, including healthcare provision, simply due to their chronological age [ 61 , 64 ].

Finally, a small number of publications ( N = 4) defined older adultsterm·key’ vulnerabilityterm·dom in terms of two dimensions, which is the result of both basic human and situational circumstances [ 43 , 51 , 57 , 74 ]. This two-dimensional vulnerabilityterm·dom is based on the idea that there are some situations and practices that add more layers of contingent vulnerabilityterm·dom to the aged condition [ 57 ]. This layering is in addition to the vulnerabilityterm·dom intrinsic to the human condition.

Dimensions of aged careterm·key vulnerabilityterm·dom By analysing in detail both basic human and situational conditions that make older adultsterm·key vulnerable, we identified in the included papers six dimensions of older adultsterm·key’ vulnerabilityterm·dom: (i) physical; (ii) psychological; (iii) relational/interpersonal; (iv) moral; (v) sociocultural, political, and economic; (vi) existential/spiritual vulnerabilityterm·dom.

A first intuitive dimension of aged careterm·key vulnerabilityterm·dom is represented in the notion of physical vulnerabilityterm·dom ( N = 14 publications). It is physical in the sense that bodily deterioration (i.e., non-pathological and pathological physical/physiological decline) tends to disproportionately affect older adultsterm·key. Non-pathological age-related deterioration are conditions that can potentially lead to the fragility syndrome: physical instability, reduced mobility, loss of power, problems with vision and hearing, among others. Pathological deterioration, on the other hand, refers to specific pathological conditions that may only affect some specific older individuals, such as illness [ 56 ], dementia [ 42 , 58 , 74 ], and disability [ 48 ].

A second dimension of aged careterm·key vulnerabilityterm·dom is psychological vulnerabilityterm·dom ( N = 18 publications). Here, we identified both strictly psychological and experiential components, the latter only if correlated with and/or impacting the psychological dimension of humans. Older adultsterm·key appear psychologically vulnerable because they are subjected to mental health changes [ 42 ] and to progressively diminishing intellectual functioning [ 66 ]. In addition to these cognitive factors, emotional factors also add further layers of vulnerabilityterm·dom [ 40 , 46 , 50 , 52 , 56 , 59 , 62 ]. For example, the cumulative loss of loved ones [ 40 ], the absence of emotional support towards the end of life [ 50 ], and the presence of negative social ties [ 47 ] are only some of the conditions that lead older adultsterm·key to perceive themselves as being psychologically vulnerable. The experiential component deals with the concept of embodiment [ 41 , 49 , 62 , 75 ] and with the psychological implications resulting from a shift from ‘an absent to a non-absent body’ [ 41 ], which predominantly occurs in old age. This body no longer supports the older one in his/her daily activities; rather, it becomes a matter of concern and requires assistance and care. Older adultsterm·key also feel psychologically vulnerable because their ‘decaying body’ impacts their personal representation [ 75 ].

A third dimension of aged careterm·key vulnerabilityterm·dom is termed relational/interpersonal vulnerabilityterm·dom ( N = 14 publications). This category deals with the impact of human interdependence in late adulthood and how that relates to vulnerabilityterm·dom. Our analysis showed that this concept could be interpreted in two ways: first, as ontological interdependence; second, as interdependence/dependence in real-world settings. While the first interpretation applies to humans in general (and by extension to older adultsterm·key), the second focuses on the ageing population specifically. Ontological interdependence means recognising the intrinsic relational and social nature of human beings [ 41 ]. Such recognition has two main implications. First, being social creatures, individualistic behaviours are against our nature [ 40 ]. Second, because we are intrinsically relational—i.e., as humans, we cannot easily avoid relations with other humans—we are also vulnerable. This latter vulnerabilityterm·dom is considered in our findings both as a positive feature (e.g., we perceive ourselves as sharing the same condition as vulnerable beings) [ 53 , 63 ] and a negative feature (e.g., we all suffer the cumulative loss of loved ones) [ 40 , 41 ].

However, most publications focus on relational/interpersonal vulnerabilityterm·dom in terms of interdependence/dependence in real-world settings. Older adultsterm·key are vulnerable insofar as they progressively become ever more dependent on others. Indeed, due to progressive decline in their physical and cognitive abilities, older adultsterm·key lose more and more control over their own daily activities [ 71 ], and, in broad terms, lose their decision-making capacity [ 52 , 68 ]. In addition to this vulnerabilityterm·dom characterising all older adultsterm·key, there are some specific conditions that make some older adultsterm·key more susceptible to further relational/interpersonal vulnerabilityterm·dom. This may occur in the case of dependent older adultsterm·key lacking adequate family support [ 47 , 60 , 71 ] and/or in the case when they have to live alone [ 73 ].

A final aspect of relational/interpersonal vulnerabilityterm·dom is found in the sexuality of older adultsterm·key. As some findings suggest, there is a stigma attached to the expression of sexuality in older adultsterm·key because of the pervasive belief that older adultsterm·key are not sexually active or that they are necessarily in heterosexual relationships [ 42 , 58 ].

A fourth dimension of aged careterm·key vulnerabilityterm·dom is what we defined as moral vulnerabilityterm·dom ( N = 7 publications). Moral vulnerabilityterm·dom can take on two meanings. In its positive sense, moral vulnerabilityterm·dom is interpreted as care for older adultsterm·key’ dignity [ 58 ], respect for their acquired wisdom [ 53 , 54 ], and attention to their moral preferences [ 72 ]. In its negative sense, it points to the risk for older adultsterm·key of being subjected to infantilisationterm·dom. Infantilisationterm·dom occurs when empathy goes unexpressed and when older adultsterm·key are treated as objects [ 56 ]. Infantilisationterm·dom also underlies the phenomenon of depersonalisationterm·dom; that is, when older adultsterm·key are deprived of their personal identity [ 69 ]. Our analysis also revealed that moral vulnerabilityterm·dom in its negative sense underlies the stigmatisation of some practices that may help this population to better cope with their personal conditions, such as preventing older adultsterm·key from receiving palliative care, causing them unnecessary pain [ 57 ].

Most publications considered older adultsterm·key’ vulnerabilityterm·dom to emerge as a result of unfair or unjust sociocultural, political, and economic conditions ( N = 22 publications). Considering only the sociocultural dimension of this vulnerabilityterm·dom, older adultsterm·key become vulnerable when they are excluded from social life and/or are isolated [ 41 – 43 , 58 , 69 ]; marginalised [ 42 , 46 ]; and stigmatised [ 42 , 46 , 48 ]. Sociocultural vulnerabilityterm·dom affects more females than males [ 50 , 63 , 73 ], and people with low levels of education compared to those who have achieve high levels of education [ 60 , 73 ]. Low levels of social support are also frequently mentioned as a condition for sociocultural vulnerabilityterm·dom [ 47 , 51 , 65 , 74 ]. Strictly related to sociocultural dimensions, some publications explicitly referred to forms of economic and political vulnerabilityterm·dom [ 42 , 45 , 47 , 50 , 51 , 56 , 61 , 63 , 64 , 66 , 73 , 74 ], the latter including also discrimination in the provision of healthcare [ 61 , 63 , 64 , 73 ], and subjection to unjust judicial systems [ 56 ].

The last dimension of older adultsterm·key’ vulnerabilityterm·dom we identified is existential/spiritual vulnerabilityterm·dom ( N = 15 publications). This kind of vulnerabilityterm·dom is part of the broader category of basic human vulnerabilityterm·dom. It refers to those existential and/or spiritual conditions that quintessentially characterise humans but are even more represented in the ageing population [ 49 , 51 , 66 , 67 , 70 ]. Older adultsterm·key are existentially and spiritually vulnerable, because they often more vividly experience human finitude [ 38 , 41 , 51 , 53 , 70 ]; that is, they feel closer to dying and they also disproportionately experience disruption of everyday competences [ 70 ]. Their vulnerabilityterm·dom thus appears as a lens through which human experiences are intensified [ 67 p. 144]. Older adultsterm·key’ existential/spiritual vulnerabilityterm·dom is also intrinsically related to the concept of ‘meaning’. In its positive sense, older adultsterm·key’ vulnerabilityterm·dom is characterised in a way that allows life experiences to be interpreted as meaningful [ 40 , 53 , 54 , 72 , 75 ]. In line with this first interpretation, being old represents an opportunity for human authenticity [ 54 ]. In other publications the dimension of existential/spiritual vulnerabilityterm·dom may have a negative connotation. In this case, older adultsterm·key experience meaninglessness and hopelessness [ 42 , 43 , 71 , 72 ].

Additional conditions/issues correlated with aged careterm·key vulnerabilityterm·dom In addition to the six dimensions of older adultsterm·key’ vulnerabilityterm·dom, we found that authors indicated that there are also some conditions correlated with older adultsterm·key’ vulnerabilityterm·dom. These may belong to different dimensions simultaneously. These other conditions are depression, loneliness, undertreatment of pain, medicalisation, living situation, and control.

Depression relates to both physical/physiological [ 42 ] and psychological vulnerabilityterm·dom [ 53 , 66 ] in terms of its interpretation as a medical or psychological condition.

Loneliness is considered to be one of the main factors correlated with vulnerabilityterm·dom. As related to psychological/experiential vulnerabilityterm·dom, it appears as the condition that enables older adultsterm·key to confront the feeling of their own nothingness and/or uselessness [ 43 ]. As related to relational/interpersonal vulnerabilityterm·dom, it refers to the reality that most older adultsterm·key are often alone and deprived of satisfying connections with others [ 43 ]. As related to existential/spiritual vulnerabilityterm·dom, it recalls the ontological separation between human beings [ 70 ].

Undertreatment of pain and medicalisation are interesting concepts, since they are not only related to physical vulnerabilityterm·dom [ 44 , 72 ] and psychological/experiential vulnerabilityterm·dom [ 68 ], respectively, but also can be interpreted as socioculturally sensitive phenomena. This means denying an older person pain relief is considered by some to be a virtuous act [ 44 ], while vulnerabilityterm·dom understood as a medical condition confers ‘the legitimation that others have to intervene in older adultsterm·key’ life [ 69 p. 1044].

When authors refer to living situation, they mean those conditions, either environmental or social, that may create vulnerable situations for older adultsterm·key. This applies not only to older adultsterm·key living in dangerous areas and/or unsafe environments [ 48 , 56 , 60 , 66 , 71 , 73 ], but also to those who are disempowered because being subjected to unnecessary hospitalisation [ 56 , 62 , 69 ], for example.

A final factor of vulnerabilityterm·dom considers the condition of control. Becoming old leads to the progressive (and physiological) loss of power and control [ 49 , 66 ]. However, besides this condition, some older adultsterm·key considered themselves illegitimately surveilled by others [ 58 , 68 ].

Means to address aged careterm·key vulnerabilityterm·dom Our analysis revealed a close connection between the ethical perspective endorsed by the authors and the suggested approach to address a given vulnerabilityterm·dom (Table 8 ). In other words, the ethical perspective through which vulnerabilityterm·dom is conceptualised informs the suggested ways to account for or address vulnerabilityterm·dom itself.

Our analysis identified three ways, or strategies, to relate to older adultsterm·key’ vulnerabilityterm·dom: (i) understanding older adultsterm·key’ vulnerabilityterm·dom, (ii) taking care of vulnerable older adultsterm·key, (iii) intervening through sociopolitical and economic measures.

Putting aside the ‘outlier’ publications (see “ General description of publications ” section), strategy (i) is advanced by authors who endorse phenomenology and existentialism, and virtue ethics perspectives. Strategy (ii) is advanced by authors who endorse a principlist approach. Strategy (iii) is advanced by authors who endorse a capability approachterm·dom, feminist ethics, public health ethics, and analytic political philosophy. Finally, mixed strategies were also evident: Supporters of care ethicsterm·dom hold that older adultsterm·key’ vulnerabilityterm·dom requires both (i) and (ii) strategies, while supporters of personalistic ethicsterm·dom hold that older adultsterm·key’ vulnerabilityterm·dom requires both (i) and (iii).

Understanding older adultsterm·key’ vulnerabilityterm·dom Proponents of phenomenology and existentialism, and virtue ethics claim that the best way to address older adultsterm·key’ vulnerabilityterm·dom is to first understand it. In five publications [ 41 , 43 , 46 , 62 , 67 ], the authors endorsed an approach that combines aspects of phenomenology and existentialism. Sensitivities of phenomenology and existentialism consider as a grounding assumption the presence of an inevitable layer of vulnerabilityterm·dom, namely basic human vulnerabilityterm·dom. At the same time, they argue that additional (situational) layers of vulnerabilityterm·dom can emerge only within the first-person perspective of the older adultterm·key and his/her experiences. While vulnerabilityterm·dom as a metaphysical status characterises all human beings and may be generalised [ 43 ], vulnerabilityterm·dom as a situational condition appears as a unique and non-generalisable tenet of the specific older adultterm·key under consideration [ 41 , 43 ]. Addressing older adultsterm·key’ vulnerabilityterm·dom therefore requires understanding the very essence of older adulthood as being intrinsically affected by some layers of basic human vulnerabilityterm·dom [ 67 , 70 ]. However, it also means addressing it by thoroughly investigating the inner feelings and sensation of specific older adultsterm·key, all of whom likely have heterogeneous experiences [ 41 , 62 ].

Two publications [ 53 , 58 ] ground their claims in a virtue ethics approach, the latter interpreted using elements of accounts of Aristotle, MacIntyre, and Swanton. Within a virtue ethics approach, vulnerabilityterm·dom as an existential condition has a very important role. Indeed, given that vulnerabilityterm·dom, dependence, and affliction are intrinsic human characteristics, the underlying philosophical assumption of virtue ethics is that it is essential to recognise and experience existential vulnerabilityterm·dom in order to fully express one’s human nature. However, it is precisely the exercise of virtues that enables individuals ‘to confront and respond to vulnerabilityterm·dom and dependence in ourselves and others’ [ 58 p. 968]. Virtues and vulnerabilityterm·dom are therefore strongly correlated. According to a virtue ethics approach, older adultsterm·key’ vulnerabilityterm·dom should be understood as an existential condition, not necessarily having a negative connotation. Moreover, since it emphasises life-encompassing moral development, virtue ethics assumes the potential for development to unfold throughout the entire life course. This means taking older individuals seriously as moral agents [ 53 ].

Taking care of vulnerable older adultsterm·key Three publications [ 38 , 44 , 52 ] used a principlist approach to ethics. Principlismterm·dom represents the major approach of contemporary Anglo-Saxon biomedical ethics. Functioning ‘as an analytic framework of general norms derived from the common morality that form a suitable starting point for biomedical ethics’ [ 76 p. 13], principlismterm·dom is based on four prima facie moral principles, namely respect for autonomy, non-maleficenceterm·dom, beneficenceterm·dom, and justice. Respect for autonomy is clearly linked to humans’ self-determination, which is usually defined as allowing one to make informed decisions about one’s own life and permitting one to act accordingly. Non-maleficenceterm·dom is essentially a translation of the Hippocratic oath, primum non nocere (i.e., first of all do not harm), while beneficenceterm·dom refers to the consequentialist duty of maximising the patient’s benefit. The principle of justice regulates the relationships between individuals regarding health, requiring also to apply fair procedures in the allocation of health resources across individuals.

Our analysis showed that authors adopting principlismterm·dom argued that the best means to address older adultsterm·key’ vulnerabilityterm·dom is to protect vulnerable individuals [ 38 ]. Protection is intrinsically related to respect for persons. As the Belmont Report suggests [ 13 ], individuals incapable of self-determination should be granted appropriate protection. Being incapable of self-determination is one of the conditions defining vulnerabilityterm·dom. We also observed that protecting older adultsterm·key means preserving older adultsterm·key’ capacity of self-determination (i.e., autonomy) as much as possible, while also promoting their well-being [ 52 ]. One threat to well-being in older adulthood is untreated pain. Protecting vulnerable adults also means actively promoting older adultsterm·key’ pain relief [ 43 ].

Intervening through sociopolitical and economic measures A third proposed strategy to address older adultsterm·key’ vulnerabilityterm·dom is to intervene through sociopolitical and economic measures so as to minimise vulnerabilityterm·dom as much as possible. Supporters of this view advocate four approaches: the capability approachterm·dom, feminist ethics, public health ethics, and analytic political philosophy. Precisely because they believe that older adultsterm·key’ vulnerabilityterm·dom is the result of unfair sociopolitical and economic contingent conditions, these authors endorse a situational definition of vulnerabilityterm·dom. It follows, then, that vulnerabilityterm·dom may be reduced by intervening through these approaches.

Two publications endorsed a capability approachterm·dom [ 45 , 65 ]. This normative framework discerns three main elements—well-being, functioning, and capabilities—and argues that freedom to achieve well-being is of primary moral importance. Well-being is interpreted in terms of people’s capabilities and function. Looking at the debate over aged careterm·key vulnerabilityterm·dom through the lens of the capability approachterm·dom means first to individuate older adultsterm·key’ well-being, functioning, and capabilities. Our analysis showed that older adultsterm·key’ well-being corresponds to autonomy, broadly considered. Functioning means remaining autonomous, while capabilities refer to the set of social assets that prevent older adultsterm·key from losing their autonomy [ 45 , 65 ]. According to the capability approachterm·dom, older adultsterm·key’ vulnerabilityterm·dom is neither a descriptive (and necessary) condition correlated to ageing, nor is an existential phenomenon. Vulnerabilityterm·dom, however, is a normative status that public health authorities must properly address and, if possible, prevent [ 65 ].

A similar answer comes from the proponents of public health ethics approaches [ 56 , 71 ] and analytic political philosophy [ 64 ]. These approaches are characterised by the conviction that health is not only an individual condition, resulting from the biological constitution of the individual herself, but is a complex phenomenon that results additionally from unjust economic systems. When applied to middle income countries [ 56 ], public health ethics is narrowly defined as the domain of ethics investigation interested in ‘social justice, poverty, and systematic disadvantage’ [ 56 p. 186]. Within these approaches, vulnerabilityterm·dom is not only a situational but also a ‘multi-layered condition’ [ 56 ], that is, the results of different simultaneous conditions. This means that vulnerabilityterm·dom should be disassembled to reveal its constituent components in order to find contextual and targeted strategies to address them (e.g., against economic vulnerabilityterm·dom, improving the pension system; against housing vulnerabilityterm·dom, increase investments in geriatric institutions). It also means that a ‘one-size-fits-all’ solution is inappropriate to address older adultsterm·key’ vulnerabilityterm·dom, the latter being the result of contingent and situational conditions. In other words, vulnerabilityterm·dom ‘is seen as a condition of lived experience reflecting the intersection of unique individual factors and proximal and distal environmental factors’ [ 71 p. 225]. The publication informed by an analytic political philosophy approach [ 64 ] focuses on discrimination in health and argues that such discrimination, often labelled as ageismterm·dom, may be the most important cause of older adultsterm·key’ vulnerabilityterm·dom, even in high income countries.

Feminist ethics approaches [ 50 , 69 , 74 , 75 ] apply the entire body of reasoning typical of public health ethics and analytic political philosophy approaches to the debate over gender. They stress that older woman are the ones mostly disadvantaged, the most vulnerable among the vulnerable. This is because more older women are materially poorer than men. Because women have a higher life expectancy, they spend part of their life without a spouse. Because women live longer than men, they present more comorbidities than men. Finally, they are usually subjected to a hostile cultural climate (e.g., are mostly considered on the basis of their physical characteristics, youth, sexual and/or reproductive functions). Against such a backdrop of vulnerabilities, authors advocating these approaches suggest that intervention should be done through sociopolitical actions. On the one hand, they promote equal treatment, equal opportunity, and equal respect at the public level to reduce existing gender-based inequalities. On the other hand, they work on those ‘social interrelations and organizational practices, through which agency is dispersed’ [ 69 p. 1045].

In addition to these situational vulnerabilities, one publication [ 75 ] also points to the impact that a ‘decaying body’ has for older women. A ‘decaying body’ appears to be more difficult to accept, because of its role in relational and care practices, as well as in reproductive practices. That author proposes to recover what she labels as an ‘empowered feminist ethics’. This effort should not only help older women to ‘deal with the bodily changes that are authentically connected to aging’ [ 69 p. 79], but also to intervene on a public level. The latter would aim to promote actions that change the social environment in which such convictions originate [ 69 , 75 ].

Mixed answers to older adultsterm·key’ vulnerabilityterm·dom Our analysis showed that authors using care ethicsterm·dom and personalistic ethicsterm·dom approaches proposed addressing older adultsterm·key’ vulnerabilityterm·dom by employing mixed strategies. Care ethicsterm·dom is an approach grounded on the conviction that there is moral significance in the fundamental elements of (care) relationships and dependencies in human life. Accordingly, care ethicsterm·dom seeks to maintain and promote care relationships by contextualising the well-being of caregivers and care-receivers in a network of social relations. Proponents of the care ethicsterm·dom perspective argue that vulnerabilityterm·dom must be properly understood and ‘digested’. At the same time, it remains extremely important to protect vulnerable older adultsterm·key, balancing instances of protection with the older adultsterm·key’ desire of autonomy [ 46 ]. It is precisely within care relationships, and through an empathic understanding between caregivers and care-receivers [ 46 ], that older adultsterm·key’ vulnerabilityterm·dom may be properly understood [ 74 ]. Such vulnerabilityterm·dom has a twofold nature, one endowed with both situational and intrinsic elements. For situational elements, it is important to realise that vulnerabilityterm·dom may become a social construction, one emerging during the healthcare encounter [ 68 ]. Indeed, ‘the transformation from lived problem to diagnosis, then to treatment plan, then to rules about what ought to be done, and finally to negotiated compliance is the form the social construction of frailtyterm·key takes in the context of health care’ [ 68 p. 54]. However, older adultsterm·key, especially when hospitalised, are also intrinsically vulnerable. This is because their vulnerabilityterm·dom results from complex lifeworld dimensions, including mood (i.e., their inner state); embodiment (i.e., their physical as well as their lived body dimensions); intersubjectivity (i.e., how they are in relation with others); and space and time (both objectively and subjectively interpreted) [ 62 ].

Finally, one publication [ 51 ] was informed by a personalistic ethicsterm·dom approach. Personalistic ethicsterm·dom draws from Schotsmans’ account (1999) and states that persons are unique and original, relational and inter-subjective, and that communication and solidarity are very important for human beings [ 51 ]. The author endorsing the personalistic ethicsterm·dom approach argued that vulnerabilityterm·dom as an existential condition should be understood in its complexity. However, when situational elements are also present—namely, lack of economic security, health problems, insufficient social support—these should be actively addressed through focused sociopolitical and economic actions. The situational elements affect some older adultsterm·key, in particular, those in developing countries.

Discussion Although concerns for vulnerabilityterm·dom are central to bioethicsterm·key reflection, the concept of vulnerabilityterm·dom is still mostly under-theorized in the corresponding literature [ 4 ], especially in the context of aged careterm·key. We addressed this theoretical shortfall in the present systematic reviewterm·mth of argument-based ethics literature by answering four research questions about the meaning of vulnerabilityterm·dom, how it differs from similar concepts like fragility, the ethical arguments for discussing vulnerabilityterm·dom in aged careterm·key ethics, and possible obligations following from recognising older adultsterm·key’ vulnerabilityterm·dom. We arrive at a more refined and nuanced systematisation of the different conceptualisations of older adultsterm·key’ vulnerabilityterm·dom as present in current bioethicsterm·key literature as a result.

While vulnerabilityterm·dom as a concept is a bit murky, some exceptions are represented by research ethics and, to a lesser extent, public health ethics. Within the former, the majority of scholars endorse the so-called ‘labelling approachterm’ [ 4 , 13 ]. This approach labels a priori individuals or groups of individuals as being vulnerable according to the presence or absence of particular characteristics, namely, lack of capacity to consent to research, increased susceptibility to coercion or exploitation, and increased risk of harm. Criticizing such an approach as being too broad [ 77 , 78 ] or too narrow [ 11 ], other scholars embrace ‘analytic approachesterm’ to understanding vulnerabilityterm·dom [ 79 ]. Rather than identifying a priori populations, they aim to define sources and implications of vulnerabilityterm·dom. Kipnis, for instance, proposes an account based on seven potential sources of vulnerabilityterm·dom understood as ‘precariousness’ [ 80 p. 108], while Hurst suggests a wider range of remedies to ameliorate the vulnerabilityterm·dom of research participants [ 3 ]. However, despite its promises, even this approach turned out to be less nuanced and context-based than originally envisaged.

In public health ethics, vulnerable populationsterm·dom are defined as ‘social groups who have an increased relative risk or susceptibility to adverse health outcomes’ [ 81 p. 70]. Although factors leading to such increased risk of adverse health outcome may vary, there is consensus in defining individuals as being vulnerable when they are incapable of safeguarding their own needs and interests adequately [ 82 p. 283]. Therefore, vulnerabilityterm·dom is considered to be both a marker of social, political, and economic disadvantage correlated with poor health conditions, and/or as a feature of those who already have some forms of ill health, which increases their risk of further ill health.

Even within these domains, however, extensive debate failed to lead to the development of a comprehensive account of vulnerabilityterm·dom [ 4 ]. Therefore, a satisfying and appropriate theorization is still missing. Reasons for this are plenty, spanning the contention that vulnerabilityterm·dom should not be used as a substantive concept [ 5 ], to the acknowledgment of the difficulties in defining this concept [ 3 ], or even fixing its meaning in its broad-ranging connotations.

If applied to our specific context of investigation, no systematic and updated work on vulnerabilityterm·dom, when referring to older adultsterm·key, is present in the literature. Here, we present an analysis of relevant publications from 1984 to 2020 appearing in the philosophical, bioethical, and medical anthropology literature. The main findings are highlighted and discussed in depth next, with the ultimate aim of gaining a better understanding of how to properly deal with vulnerable older adultsterm·key.

Basic human vulnerabilityterm·dom versus situational vulnerabilityterm·dom: general considerations The first main finding from our analysis is that the way vulnerabilityterm·dom is conceptualised in the included publications is in line with the way the same concept is discussed in the current philosophical and bioethicsterm·key literature. In the 38 publications we analysed, the authors tend to support one of two views of vulnerabilityterm·dom. First, vulnerabilityterm·dom is an inherent trait of human nature, an ontological condition of our own humanity, belonging to both embodiment – in turn related to propensity to disease and sickness, to impairment and disability, but also to death [ 7 p. 29] – and sociality and interdependence [ 9 ]. This is also referred to as basic human vulnerabilityterm·dom. Second, vulnerabilityterm·dom is the consequence of contingent unfair social, political, economic conditions; this also is referred to as situational vulnerabilityterm·dom. While the first view of vulnerabilityterm·dom has appeared in the literature under the guises of persistent [ 83 ], philosophical [ 1 ], anthropological [ 2 ], universal [ 9 ], or existential [ 39 , 40 ] vulnerabilityterm·dom, the second view has been mainly referred to as variable [ 83 ], political [ 1 , 2 ], contingent [ 11 , 39 , 40 ], or extrinsic [ 11 ] vulnerabilityterm·dom. Despite differences in their nomenclature, their content largely overlaps. Only in one publication did the author refer to both kinds of vulnerabilityterm·dom [ 51 ], recognising that basic human and situational vulnerabilityterm·dom are not necessarily mutually exclusive [ 51 , 55 , 84 , 85 ]. His view of vulnerabilityterm·dom is that the two may actually coexist, with one encompassing a more complex and multi-layered understanding of vulnerabilityterm·dom (see below). These two views of vulnerabilityterm·dom are mainly supported by different philosophical and bioethical approaches. Whereas the basic human vulnerabilityterm·dom perspective is mainly advanced by authors leaning towards continental philosophy—in particular phenomenology and existentialism, and by advocates of ethics of care—the situational vulnerabilityterm·dom perspective is advanced by authors advocating analytic philosophy and social science approaches.

In the context of aged careterm·key, supporters of basic human vulnerabilityterm·dom tend to conceive of aging as a condition of increased basic human vulnerabilityterm·dom, while supporters of situational vulnerabilityterm·dom claim that aging may be conceived of as a condition of increased situational vulnerabilityterm·dom. Despite their differences, both accounts share the idea that older adultsterm·key already are, or may become, more vulnerable, because some of the conditions that determine vulnerabilityterm·dom itself are increasing. For the basic human vulnerabilityterm·dom view, these conditions include ever-increasing human finitude with age (experiencing human mortality more vividly). For situational vulnerabilityterm·dom, these conditions include contingent extrinsic circumstances. Few exceptions exist, since the authors of four publications [ 36 , 44 , 51 , 65 ] recognised the twofold nature of aging as a condition of both basic human vulnerabilityterm·dom and situational vulnerabilityterm·dom. Interestingly, our analysis showed that older adultsterm·key’ vulnerabilityterm·dom is never framed in terms of ‘pathogenic vulnerabilityterm·dom’ [ 4 ], that is, vulnerabilities generated by misplaced or wrong answers to pre-existing vulnerabilities. However, if we focus on the ‘generators’ of pathogenic vulnerabilityterm·dom’ as identified by Rogers and colleagues – namely, ‘morally dysfunctional interpersonal and social relationships characterized by disrespect, prejudice, or abuse, or by sociopolitical situations characterized by oppression, domination, repression, injustice, persecution, or political violence’ [ 4 p. 25] – then some interpretations of situational vulnerabilityterm·dom may fall in this category. This occurs, for instance, with wrong answers to ‘relational/interpersonal vulnerabilityterm·dom’ in case of dependent older adultsterm·key. Older adultsterm·key subjected to unnecessary hospitalisation or institutionalisation [ 56 , 62 , 69 ] – what we referred to as vulnerabilities related to ‘living situation’ – or illegitimately surveilled by others [ 58 , 68 ] – what we referred to as vulnerabilities related to ‘conditions of control’ – may provide some examples of pathogenic vulnerabilityterm·dom. Again, some forms of ‘moral vulnerabilityterm·dom’ in its negative connotation may be considered as examples of pathogenic vulnerabilityterm·dom: preventing older adultsterm·key from receiving palliative care [ 57 ] as a consequence of stigmatisation goes precisely in this direction.

Another major finding of our analysis of the meaning of vulnerabilityterm·dom in the context of aged careterm·key relates to dimensions of aged careterm·key vulnerabilityterm·dom. We call these dimensions (i) physical; (ii) psychological; (iii) relational/interpersonal; (iv) moral; (v) sociocultural, political, and economic; and (vi) existential/spiritual vulnerabilityterm·dom. By considering them as a whole, it becomes apparent that they map onto known defining features (and related vulnerabilities) of the human person. This observation gives weight to the view that vulnerabilityterm·dom represents an inherent feature of humans, whereby being human and being vulnerable are largely coextensive notions. At the same time, however, the overlap between being human and being vulnerable is not a perfect match. The notion that the concept of vulnerabilityterm·dom encompasses some fundamental traits of being human (e.g., experiencing finitude, being susceptible to physical and/or emotional wounds), does not mean that some other human traits realised in the future will also map onto the concept; they may not. It is recognised that this is true to the extent that being human is also defined, among others, by the capacity of being a rational agent, one endowed with moral agency, one looking for meaning, one open to transcendence, etc.

By defining vulnerabilityterm·dom as a fundamental human trait, one may assume that vulnerabilityterm·dom is a morally neutral notion. However, our analysis of the literature showed that vulnerabilityterm·dom is mostly a value-laden concept, endowed with both positive and negative connotations. For example, vulnerabilityterm·dom is clearly endowed with positive meaning when it is conceived of as a fundamental condition for human interconnectedness. This condition promotes genuine relations (relational/interpersonal vulnerabilityterm·dom). Or when one’s vulnerabilityterm·dom in late adulthood becomes an opportunity for authenticity, it may allow one to look at one’s life as acquiring new meanings (existential/spiritual vulnerabilityterm·dom). On the other hand, this notion of vulnerabilityterm·dom may take on a negative connotation insofar as it subjects older adultsterm·key to infantilisationterm·dom, depersonalisationterm·dom, and objectification (moral vulnerabilityterm·dom) but also to isolation, marginalisation, and stigmatisation (sociocultural vulnerabilityterm·dom).

One of our research questions concerned the potential correlation between the acknowledgment of vulnerabilityterm·dom and corresponding moral obligations. Accordingly, we asked whether vulnerabilityterm·dom should be regarded as an independent moral concept, one that can generate moral obligations per se, or whether responses to vulnerabilityterm·dom should necessarily appeal to other concepts or values (e.g., respect for persons, preventing harm). This also relates to other related questions, namely, whether moral obligations uniquely follow from the recognition of situational vulnerabilityterm·dom, or are generated by basic human vulnerabilityterm·dom as well; and to what, if any, these moral obligations amount to. This is a compelling and debated question in the philosophical and bioethical literature on vulnerabilityterm·dom. The majority of scholars do claim that vulnerabilityterm·dom is per se a source of moral obligations [ 86 – 88 ], though they variably interpret the content of such obligations, as well as the definition of who is responsible for fulfilling these obligations. Drawing from the consideration of vulnerabilityterm·dom being related to relationships of dependency and interdependency which may expose human beings to harm and exploitation, Goodin, for instance, formulates the ‘Principle of protecting the vulnerable’ [ 86 ]. In his view, we have an obligation to act so as to prevent harms to, or protect the interest of, those who are especially vulnerable to our actions and behaviours [ 86 ]. More recently, Reader claims that vulnerabilities arise from needs, that we, as humans, all have [ 88 – 90 ]. However, in his view, not all needs are equally morally demanding, but only ‘vital needs’, the latter not being limited to bodily sustenance and protection, but defined broadly in relation to context-specific situations and personal identity [ 88 ]. On the other side of the spectrum, other scholars suggested that moral obligations cannot derive from vulnerabilityterm·dom alone but from vulnerability-related factors. Hurst, for instance, argues that is ‘the increased likelihood of incurring additional harm or greater wrong’ [ 3 p. 195] which creates the obligation to protect those who are more than ordinarily vulnerable.

In our included papers, it is not only situational vulnerabilityterm·dom [ 44 , 45 , 50 , 51 , 53 , 56 , 64 , 65 , 69 , 71 ], but also basic human vulnerabilityterm·dom [ 43 , 44 , 46 , 53 ], that is considered a source of moral obligations. Regarding the content of moral obligations arising from vulnerabilityterm·dom, most of the publications we analysed focused on and promoted aged careterm·key in broadly conceived terms [ 38 – 46 , 48 , 50 , 52 , 57 , 59 , 63 , 68 , 69 , 72 , 74 , 75 ]. In particular, one’s attitude towards care, which is interpreted as both understanding the vulnerabilityterm·dom of and protecting older adultsterm·key, constitutes the most appropriate and fundamental response to vulnerabilityterm·dom. This finding strengthens the idea that care is a defining practice of being human. Care and vulnerabilityterm·dom are intrinsically linked as instances of humans. This does not mean, however, that vulnerabilityterm·dom is ‘erased’ once it is recognised as such. Rather, it means that only after having recognised the existence of a universal basic human vulnerabilityterm·dom and after having understood that some human beings are more vulnerable than others, a proper and targeted response may then be put in place. This is especially true for advocates of situational vulnerabilityterm·dom.

Older adultsterm·key’ vulnerabilityterm·dom as a multi-dimensional concept When grappling with the concept of vulnerabilityterm·dom in a concrete way, the authors end up integrating elements of both basic human vulnerabilityterm·dom and situational vulnerabilityterm·dom. This is the case even though almost all the authors claimed to endorse just one of the two accounts. It seems reasonable to suggest, then, that a binary understanding of the concept of vulnerabilityterm·dom in aged careterm·key is inappropriate.

Our systematic reviewterm·mth provides some evidence towards the understanding of vulnerabilityterm·dom in aged careterm·key as preliminarily conceptualised by some scholars in contemporary bioethicsterm·key. The current tendency is to characterise older adultsterm·key’ vulnerabilityterm·dom in terms of layers [ 84 , 85 , 91 ], or, as our analysis showed, in terms of dimensions of vulnerabilityterm·dom, rather than populations that are a priori vulnerable. The a priori notion is still the prevailing tendency in research ethics [ 15 – 17 ], mainly for pragmatic and precautionary reasons.

This systematic reviewterm·mth also revealed a perspective on vulnerabilityterm·dom that holds that a stable (i.e., age-independent) dimension of vulnerabilityterm·dom can be identified, one that pertains to all humans. This is reasonable since we all share the same (finite) human condition. However, this new understanding also allows for some dynamic dimensions of vulnerabilityterm·dom. As dynamic dimensions are not necessary conditions, they may or may not be present. Situational conditions (e.g., socioeconomic, political, unfair conditions) and fundamental dimensions pertaining to human life (e.g., progressive bodily deterioration) determine this dynamism.

If a proper understanding of vulnerabilityterm·dom is partly a matter of recognising that layers or dimensions of vulnerabilityterm·dom exist, then vulnerabilityterm·dom is not necessarily a black or white condition but may be a condition comprising various degrees of vulnerabilityterm·dom. Moreover, such a view permits one to foresee conditions that render the same person, or category of persons, as situationally vulnerable in some instances but not in others. One may become more or less vulnerable when additional levels of vulnerabilityterm·dom are acquired or lost during the course of life.

Finally, if vulnerabilityterm·dom is a multidimensional and complex phenomenon, then the objections raised in bioethicsterm·key literature to ‘monodimensional’ accounts of vulnerabilityterm·dom, either situational or basic human, tend to collapse. Indeed, considering vulnerabilityterm·dom only as a trait of human nature may have the implication of ‘naturalising’ vulnerabilityterm·dom [ 91 ], considering it as something that ‘cannot be reduced or remedied’ [ 1 p. 397], that is, an unavoidable phenomenon related to human existence. On the other hand, interpreting vulnerabilityterm·dom only as the consequence of situational or contingent situations, may present the danger of non-acknowledging some fundamental traits of the human condition, e.g., the precariousness deriving from being mortal, considering these traits as personal deficits, rather than essential human features. In other words, if vulnerabilityterm·dom is both a defining characteristic of our own humanity and an additional condition affecting some people in specific contingent situations, then understanding vulnerabilityterm·dom, taking care of vulnerable persons, and intervening through sociopolitical and economic measures all become strategies to be synergistically adopted to respond to vulnerabilityterm·dom.

Strengths and limitations The main strength of this systematic reviewterm·mth is the large number of publications that contributed to our analysis. Most of them were published in the last five years. Also, the analysed publications reported on studies conducted in countries across the globe. Therefore, we believe these characteristics strengthened our conclusions.

Although our study produced new insights into the meaning, foundations, and uses of vulnerabilityterm·dom as an ethical concept in the literature on aged careterm·key, it had a few limitations. Some may question that the variety of expressions used (vulnerabilityterm·dom, frailtyterm·key, fragility) may have potentially created some confounding factors in results comparisons. However, we considered this variety to be acceptable as long as these notions were used as synonyms of vulnerabilityterm·dom in the publications and were used within argument-based reasoning, rather than strictly as medical terms. Secondly, we considered only publications written in English. Moreover, this research was conducted before the Covid-19 pandemic, so any potential impact it might have had on the understanding and uses of the concept of vulnerabilityterm·dom were precluded. Intuitively, it is reasonable to assume that older adultsterm·key’ vulnerabilityterm·dom was greatly impacted [ 92 ]; future ethical analyses will determine whether the Covid-19 pandemic prompts us to modify pre-pandemic conclusions. Investigations about older adultsterm·key’ vulnerabilityterm·dom before and after Covid-19 may be highly relevant for future lines of research, especially those drawn towards understanding how vulnerabilityterm·dom as an ethical concept affects delivery of healthcare to older individuals.

Supplementary Information Additional file 1 . Example of conceptual schemeterm.