Table 1.

Subject Characteristics, Methods, and Outcomes of Included Studies.

Author (Date)	Country	Study purpose	Study design	Specific study design	Setting	Sample description	Type of cognitive impairment	Decisions of interest	Primary outcome or study variables of interest	Findings/Results
Aaltonen et al. (2021)	Finland	To detect different ways people with memory disorder and their spouse CG strive and influence formal care; to recognize situations where their influence is described as restricted or nonexistent.	Qualitative	Descriptive	Participant’s homes or the Alzheimer Society office	N = 34 persons with memory disorders, or their spousal CG	Memory disorder (diverse cognitive health status)	Influence of people receiving care and their spouses’ will on care (content, quality, delivery)	Identified limitations and diversity in how people can influence care from formal providers; demonstrated importance of family CG	4 themes: acquiescence; negotiating care; lack of influence; taking control
Adekpedjou et al. (2019)	Canada	To assess the effect of training home-care teams in interprofessional SDM on the proportion of CGs who report being active in housing decisions involving cognitively impaired older adults.	Quantitative	Pragmatic cluster randomized trial	Health centers	N = 296 CGs from 16 health centers	Dementia	Housing	The proportion of CGs who reported playing an active role in decision making; the matches between preferred option and decision made; impacts on the outlying cluster; CGs’ preferred health-related housing option, the decision made, decisional conflict, decision regret, or burden of care	Intervention increased the proportion of CGs who reported an active role in decision making by at least 12%; increased the proportion of matches between the decision-making role a caregiver preferred and the role they assumed; SDM training had less of an impact on the outlying cluster and no effect on CGs’ outcomes.
Ampe et al. (2016)	Belgium	To pilot ’we DECide’ and assess its influence on ACP policy and practice in nursing home dementia care units and barriers for its implementation.	Mixed Methods	Quasi-experimental pre-test-post-test	Dementia care units in nursing homes	N = 90 nursing home staff from 18 dementia care units	Dementia	ACP for end-of-life care	ACP-audit score; barrier; frequency of ACP or involvement of families and residents	Following “we DECide” training, nursing home policy regarding ACP improved significantly, though the actual practice did not; intervention had no significant impact on frequency of ACP or involvement of families and residents.
Bilodeau et al. (2019)	Canada	To identify patient decision aids’ (Decision boxes) features for older adults with dementia and their family CGs.	Mixed Methods	Multiple case study within an iterative user centered design approach	Community based healthcare	N = 23 PWDs (≥ 75 years), their 27 CGs (1, friend)	Dementia	Dementia care (case 1. choosing a non-pharmacological treatment to manage agitation, aggression, or psychotic symptoms; case 2. deciding whether to stop driving following diagnosis; case 3. deciding whether to prepare a power of attorney)	The revised template designed for patient decision aids to meet the needs of adults living with dementia and their CGs better	Participants recommended adding pictures and diminishing complexity; appreciated check-boxes; mixed feedback on providing information regarding quality of evidence but overall positive regarding the decision aid for assistance in decision-making.
Bolt et al. (2019)	Netherlands	To investigate relatives’ experiences with end-of-life care for PWDs, comparing the nursing home and home setting.	Qualitative	In-depth interviews, thematic analysis	Nursing home vs. home setting	N = 32 bereaved of PWDs	Dementia	End-of-life care	Relatives’ experiences with care for PWDs in the final months of life	In both settings, open discussion with professionals aided decision-making about end-of-life care; regardless of discussion of end-of-life wishes with the PWD, relatives faced challenges and questioned about ’moral rightness’ of their decisions.
Boucher et al. (2019)	Canada	To explore burden of care for informal CGs who had made housing decisions on behalf of a cognitively impaired older person.	Quantitative	Cross-sectional study (secondary analysis of a cluster randomized trial)	Community health and social services centers in rural and urban setting within the Province of Quebec	N = 296 CGs (from 16 centers) of a cognitively impaired older person receiving service from home care team	Dementia	Housing	Factors associated with higher burden of care	Greater perception of joint decision-making process was linked to a higher burden of care
Davies et al. (2021)	UK	To explore the decision-making process and factors that influence decision-making in dementia end of life care and to produce a model of decision-making in the context.	Qualitative	Semi-structured inteviews, thematic analysis	Community	N = 11 PWDs, 21 CGs (including 6 dyads)	Dementia	End-of-life care	Process of making decisions and factors influencing decisions	Contextual influencing factors: personal preferences; advanced care planning and Lasting Power of Attorney; capacity, health and wellbeing of the PWD; support from others and clarity of roles. Process of making decisions: identifying the decision maker or team; sharing and exchanging information; clarifying values and preferences; managing and considering emotions; considering the feasibility of options; balancing the preferred choice and the actual choice; implementation and reflecting on outcomes.
Dooley et al. (2018)	UK	To explore how doctors involve patients with dementia in decisions to start medication.	Quantitative	Observational	Memory clinics within UK National Health Service trusts in either London (urban) or Devon (rural)	N = 71 PWDs, 67 companions, 21 medical doctors	Dementia	Medication	Patient participation in the decision on medication	No association between patient acceptance or resistance and whether medication was prescribed; patients significantly less satisfied with communication when not given a choice in taking the medication.
Elidor et al. (2020)	Canada	To identify factors associated with decision regret among informal CGs engaging in housing decisions for cognitively impaired older adults.	Quantitative	Cross-sectional study (secondary analysis of a cluster randomized trial)	Home care settings	N = 296 CGs	Dementia	Housing	Factors associated with less decision regret; factors associated with more decision regret	The perception that a joint decision-making process occurred was linked to less decision regret
Garvelink et al. (2019)	Netherlands	To assess the extent to which housing decisions for PWDs with their formal and informal CGs correspond to an interprofessional (IP) SDM approach and their experience with decision making.	Qualitative	Secondary data analysis on material collected in a qualitative study with a longitudinal multiperspective design, semi-structured individual interviews	Community	N = 23 care networks (23 PWDs, 2 CGs, and 2 HCP for each)	Early or moderate dementia	Housing for PWDs	The extent the decision-making process about housing for PWDs with their formal and informal CGs corresponds to an IP-SDM approach	IP-SDM model is overall a useful model in dementia care networks. Limitations: decreased involvement of PWDs over time; no deliberation among all network members to reach a common understanding; lack of collaboration; poor match between preferences and the actual decision made
Givens et al. (2018)	US	To describe aspects of ACP among PWDs and examine the association between ACP and health care proxy acceptance of patients’ illness.	Quantitative	Cross-sectional, observational	Community (outpatient geriatric and memory disorder clinics)	N = 62 health care proxy of PWDs	Dementia (mild, moderate/severe)	Advance care planning	Proxy acceptance of dementia	31% of patients had communicated with their physician regarding preferences for care; 77% communicated with the HCP. 44% of proxies wanted more discussion with the patient regarding care preferences. The proxies having discussed care preferences with the patient was associated with greater acceptance of the patient’s illness.
Goossens et al. (2020)	Belgium	To explore how health professionals and residents with dementia perceive the level of SDM during ACP conversations ; to investigate professionals’ perceptions of the importance of SDM, their perceived competence and self-reported frequency of utilizing SDM.	Quantitative	Cross-sectional	Nursing homes	N = 311 care and non-care professionals, 42 residents, 4 external raters	Dementia	Advance care planning (individual goals and preference)	Level of SDM rated by health professionals, residents or families, and external raters, and health professionals’ perception of the importance of SDM	Average achieved level of SDM: 71.53/100 by professionals, 81.11/100 by residents, 26.97/100 by external raters. 23.8% of residents referred to ACP as the topic of the conversation. Although professionals considered SDM to be important, the scores of the frequency and competence with which these skills were practiced were lower.
Griffin et al. (2020)	US	To understand what potential best practices are for including CGs of people with Alzheimer’s disease and related dementias (ADRD) into clinical appointments from the perspective of CGs and people with ADRD.	Qualitative	Cross-sectional	Online focus groups	N = 42 spousal CGs, 36 non-spousal CGs, 15 PWDs	ADRD	Involvement of CGs in clinical practice	Best practices for engaging CGs	Best practice for decision making train providers in SDM and how to resolve conflicts with CGs and PWDs; help navigate SDM processes; involve multiple people (CGs); consider CG capacity and values; set a pattern of SDM early in the disease process; value the significance of non-spousal CG’s role.
Groen-van de Ven et al. (2017)	Netherlands	To explore how PWDs, their informal CGs and their professionals participate in decision making about daycare; to develop a typology of participation trajectories.	Qualitative	Prospective, multiperspective	Community living, nursing homes	N = 19 PWDs, 36 CGs, 38 HCPs	Early and moderate stages of dementia	Daycare	The way care networks proceed through the process of decision making about daycare	Decision making process: initial expectations about daycare; negotiating about trying daycare; trying daycare. Types of participating trajectories: working together positively toward daycare (type 1), bringing conflicting perspectives together toward trying daycare (type 2), not reaching a commitment to try daycare (type 3)
Groen-van de Ven et al. (2017)	Netherlands	To describe the process elements of decision-making in dementia care networks; to enrich the model of collaborative deliberation to facilitate SDM in dementia care networks.	Qualitative	Secondary analysis of interviews	Community living, nursing homes	N = 23 PWDs, 44 CGs, 46 HCPs	Dementia	Dementia care (not explicitly indicated)	The model of collaborative deliberation in dementia care networks	The enriched model: preparatory work (constructive network engagement, recognizing the need for a decision, defining what to decide on), rational discussion (developing alternatives, constructing preferences through deliberation, and trying out alternatives), coalitions (multiple preferences integration, evaluating decision-making)
Groen-van de Ven et al. (2017)	Netherlands	To examine the decisions made and the related key events in the trajectories of care networks.	Qualitative	Prospective, multiperspective	Community living, nursing homes	N = 23 PWDs, 44 CGs, 46 HCPs	Beginning to advanced stages of dementia	Decisions with consequences for daily life over the course of time	Decisions made, when decisions occur, characteristic patterns in the sequence of decisions in the care networks	Decisions made: managing daily life with the dementia, arranging care and support, living in society, and representing the PWD. Key events in the decision trajectories: (beginning stage) concerns before the diagnosis, the diagnosis, the inactivity of the PWD, and safety incidents; (middle stage) safety incidents, inactivity of the PWD, 24-hr monitoring, hospitalization, and nursing home admission; (advanced stage) nursing home admission, adjustment issues, and switching between wards. These patterns differ between people living alone and those with an in-live informal CG.
Groen-van de Ven et al. (2018) Abstract only	Netherlands	To describe the challenges of SDM in dementia care networks.	Qualitative	Multi-perspective qualitative study using face-to-face interviews; content analysis	Community	N = 113 (23 care networks = 23 PWDs, 44 CGs, and 46 HCPs)	Dementia	Dementia care	Challenges of shared decision-making	Challenges: adapting to a situation of diminishing independence, including shifting roles in the decision making; tensions in network interactions, resulting from different perspectives and interests and requiring agreement about what constitutes a problem in the situation; timing decision well
Hamann et al. (2011)	Germany	To analyze the preferences of patients with amnestic mild cognitive impairment (aMCI) and mild AD regarding different aspects of decisions; to correlate these findings with different measures of patient decision-making capacity; to explore the views of the patients’ relatives and of the referring physicians.	Quantitative	Cross-sectional	Memory clinic	N = 100 PWDs, 99 relatives, and 93 of their referring physicians	aMCI and mild AD	Healthcare-related decision	Patient participation preferences	Patients prefer to have the greatest say in social decision making and want their relatives to have little influence on social or medical decisions. Higher patient confidence in their decisional capacity and their MMSE score were predictors of higher patient participation preferences. There was only weak correlation between patient’s relative’s, and physician’s estimate, MacArthur Competence Assessment Toll for Treatment of the patients’ decisional capacity.
Hill et al. (2017)	UK	To identify the aspects of end-of-life care for PWDs that are most important to them and their CGs.	Mixed methods	Q-methodology	Community	N = 57 (14 PWDs, 21 CGs, and 22 bereaved CGs)	Early-stage dementia	End-of-life care	The views shared by PWDs, current family CGs and bereaved CGs about the elements of care considered important towards and at end-of-life	Shared viewpoints: family involvement, living in the present, and pragmatic expectations. Areas of consensus: compassionate care, decisions being made by healthcare professions, and information availability when making decisions.
Kwak et al. (2019)	US	To understand ADP and decision making among PWDs and CGs.	Quantitative	Cross-sectional	Rural health care facilities (outpatient family practice clinics)	N = 47 CGs of PWDs	AD and related dementias	End-of-life care	PWD’s advance directive completion and the role of the family in proxy decision making	60% of PWDs had completed an advance directive; 57% preferred equally SDM between family (including the PWD) and physicians. Under a hypothetical scenario for PWDs, 40% of the CGs chose comfort; 55% palliative care treatment. Hispanic PWDs were less likely to complete an advance directive and to choose only pain and symptom management than non-Hispanic White counterparts.
Mariani et al. (2018)	Italy, Netherlands	To analyze the effects of training nursing home staff in the implementation of SDM on agreement of residents’ ’life-and-care plans’ with the recommendations and on family CGs’ quality of life and sense of competence, and staff’s job satisfaction.	Mixed methods	Intervention	Nursing home	N = 49 residents and CGs, 34 HCPs	Dementia	Dementia care	Agreement of residents’ ‘life-and-care plans’ with the recommendations (primary outcome), family CGs’ quality of life and sense of competence, and staff’s job satisfaction (secondary outcomes)	Most care plans showed a high level of agreement with the care planning recommendations and improvement in the number of clear problem statements. In Italy, significant improvements were also found regarding specific care objectives, documentation of objectives met and of residents and families’ involvement. No impact was found on secondary outcomes.
McCabe et al. (2019)	UK	To measure SDM when starting cholinesterase inhibitors; to investigate associations with contextual factors and explore satisfaction and experience of the diagnostic meeting.	Quantitative	Observational	Memory clinics	N = 74 PWDs, 69 companions (5 patients were not accompanied), and 21 doctors	Dementia	Starting cholinesterase inhibitors	Decision-making subscale of the Autonomy Preference Index; satisfaction with Decision scale	Low SDM scores with 50% of patients and 1/3 of companions reporting negative experiences of receiving a diagnosis of dementia. Patients with mixed dementia were more involved in decision-making compared with AD alone.
Meyer et al. (2019)	Australia	To outline the development of a discussion tool that can support service providers to provide choice for PWDs and their CGs in addressing high falls risk factors.	Quantitative	Longitudinal study (baseline, 6-, 12-month assessments)	Community care agencies	N = 25 dyads (PWD and CG)	AD, dementia with Lewy bodies, mixed dementia, vascular dementia, and frontotemporal dementia	Falls prevention strategies	The discussion tool, a person-centered approach to addressing high risk falls risk factors	Capacity and desire to participate meaningfully in their HCPs impetus for providing genuine choice through SDM in service provision, for which this tool is useful.
Murphy and Oliver (2012)	UK	To explore whether Talking Mats (TM) could help PWDs and family CGs feel more involved in decisions about managing their daily living than using their usual communication methods.	Mixed methods	Questionnaires, focus groups	Home setting	N = 18 dyads of PWD and CG	Dementia	How participants manage their daily living including personal care, getting around, housework, activities	Participants’ feeling of involvement in discussions when using the TM framework, compared with their usual methods, and their satisfaction with the outcome of the discussions	The TM significantly increased feelings of involvement and overall satisfaction with the discussion for PWDs and family CGs. Both PWDs and family CGs reported that the TM helped them in the SDM process.
Reitz and Dalemans (2016)	Netherlands	To observe the effect of Talking Mats (TM) on shared decisions in communication with PWDs; to assess if TM affects the use of language by PWDs in conversation; to get insight in the usability of the Dutch version of TM for PWDs and their relatives.	Mixed methods	Quasi-experimental with semi-structured interviews	Nursing homes and a dementia self-help group	N = 6; all in stage 2 of AD, all between 84-90 years old; 5 women, all with their daughters	AD	Three conversations with regard to planning daily activities and care	Usability of Talking Mats in SDM process; difference in the use of language of the participants with AD	The Dutch version of Talking Mats led to an increase in SDM practices about daily activities and care. It is not clear whether Talking Mats has an effect on the use of language of PWDs. Participants stated the TM was easy to use and made it possible to understand the thoughts of one another more.
Smebye et al. (2012)	Norway	To gain a better understanding of how PWDs participated in making decisions about health care and how their family CGs and professional CGs influenced decision making.	Qualitative	Multi case design, semi-structured interviews (family CGs, HCPs), observation (PWDs, HCPs)	Home settings, sheltered housing or a nursing home	N = 10 triads (PWD, family CG, HCP)	Moderate dementia	Decisions concerning daily activities, medical care and moving to sheltered housing or a nursing home	How PWDs participated in making decisions about health care and how their family CGs and HCPs influenced decision making	SDM seemed to be the most typical pattern in decision making, demonstrating that PWDs were dependent on others. Helpers compensated for lost abilities or facilitated the use of retained functions. There was typically an exchange of information and a questioning and answering pattern in the dialogue.
Span et al. (2015)	Netherlands	To examine what PWDs, CGs, and case managers think of the user-friendliness of the DecideGuide, whether users were satisfied with it and how easily they accepted it, and what value they put on it for decision-making.	Mixed methods	5-month field study; structured interviews (PWDs, CGs, case manages), observations of home visits, information that the participants logged in the DecideGuide	Community	N = 19 (4 PWD, 12 CGs, 3 case managers)	Mild to moderate dementia	Shared decisions about healthcare	User-friendliness of the chat for PWDs, CGs, and case managers	Participants felt more involved and shared more information about daily issues than they had done before using the DecideGuide. They deemed the new tool valuable in SDM . The chat function specifically appeared powerful in helping members engage with one another.
Stevenson et al. (2016)	Northern Ireland	To understand the risks that present most concern to family CGs, attitudes and approaches of this group towards risk; to examine how information about risks is shared between family CGs, care recipients and professionals working in dementia care.	Qualitative	Focus groups	Health and Social Care Trust areas which deliver publicly funded health and social care services	N = 22 dyads	AD, vascular dementia, dementia with Lewy Bodies, frontotemporal dementia	Risk communication regarding activities of daily life	The risks that present most concern to family CGs; attitudes and approaches towards risk	Discussions about risk were related to medical treatment, supports in the home, and health and safety issues. The process of risk communication appeared as significant as the outcome for family members. Discussions with PWD tended to revolve around raising awareness of risks. Risk communication with professionals and the PWD could effectively support CGs in managing risks in the community, identifying solutions to risks, and modifying concerns.
Stirling et al. (2012)	Australia	To explore the meanings given by stakeholders to a decision aid to support dementia CGs to select community-based respite services.	Qualitative	Secondary analysis of interviews (CGs, expert advisors) and focus groups (HCPs)	Community	N = 18 (12 CGs, 3 expert advisors, 3 HCPs)	Early to moderate dementia	Selecting community-based respite services	Meanings given by stakeholders to a decision aid to support dementia CGs to select community-based respite services; HCPs’ perspectives on decision support needs and their clients’ perspective	There were differences amongst HCPs regarding the type of information they believed was appropriate to share with CGs. Many participants felt that CGs would benefit from the decision aid, and some felt that the use of aid would be useful for HCPs to work through with CGs.
Tilburgs et al. (2020)	Netherlands	To explore the implementation of the ACP educational intervention for general practitioners (GPs); to explore the impact of the intervention’s mechanisms on daily practice and the experiences of GPs, PWD and their CGs.	Mixed methods	Clustered randomized control trial; descriptive statistics; focus group interview of intervention providers	Two workshops for GPs in primary care practice	N = 36 GP, 140 dyads of PWD and CGs	Unspecified dementia	Medical and non-medical care preferences, not restricted to end of life care (ACP planning)	Intervention’s reach and acceptability, adoption and appropriateness of ACP in daily practice; experiences of GPs, PWD and their CGs.	Most CGs indicated that starting ACP that suited the PWD’s needs influenced their current situation and quality of life and that ACP provided tranquility, clarity, increased their knowledge about dementia, improved their contact with their GP and increased their trust in healthcare professionals. Some felt that ACP had mostly focused on the PWD’s illness and medical preferences.
Visser et al. (2018)	Netherlands	To describe naturalistic clinician-patient communication during routine diagnostic clinical consultations in a wide range of memory clinics.	Mixed methods	Multicenter, observational study; audio-recorded diagnostic consultations; surveys for clinicians and patients/CGs	Memory clinics	N = 41 clinicians interviewing a total of 136 patients/CGs	Unspecified dementia; had to score 18 or above on the Mini-Mental State Examination	Diagnostic testing (neuropsychological assessment/testing, structural imaging by means of MRI/CT, amyloid testing or other relevant tests)	Naturalistic clinician-patient communication during routine diagnostic clinical consultations	In almost all pretesting consultations in which diagnostic testing was addressed, one or more decisions were made on testing. Clinicians often presented decisions as a recommendation rather than an option. Observed clinician behavior to involve the patient in the decision-making process was limited. PWDs/CGs rarely expressed if and how they would like to be involved in decision-making.
Casey et al. (2015)		To identify professional competencies in facilitating SDM in care networks of PWDs.	Qualitative	Interviews and focus groups	Nursing home	N = 15 networks (15 PWDs, 2 CGs, and 2 professionals)			Professional competencies in facilitating SDM	Identified competencies and attitudes: facilitating patient autonomy of the PWD and CGs; planning decisions over time; facilitating reciprocal information-exchange within the care network; using a step-wise approach of reaching shared decisions; and sharing responsibility for decision-making within the care network