Research design and methods

This scoping review was conducted following the methodological framework proposed by Arksey and O’Malley19 and further refined by the Joanna Briggs Institute.20 This review is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR).21 The protocol for this review was preregistered on the Open Science Framework (OSF) (https://osf.io/tx29b/overview)

To guide study selection, eligibility criteria were defined using the Population–Concept–Context framework recommended for scoping reviews. The population of interest was adults aged 65 years and older receiving healthcare in East Asian countries and regions. Although various international definitions of older adults exist, this review adopted 65 years as the threshold, consistent with demographic reporting practices in East Asia and widely used international aging indicators.11 Where explicitly reported, studies were included if they explicitly targeted participants aged 65 years or older. Studies were also considered eligible when the reported mean or median age of the sample was 65 years or older, following the eligibility criteria used in a previous systematic review of SDM in older adults with multiple chronic conditions.12 The concept of interest was SDM, specifically reported barriers and facilitators to SDM. The context included any healthcare setting within East Asian health systems. For the purpose of this review, East Asia was defined based on commonly used geographic classifications (eg, United Nations Statistics Division) and included the following countries and regions: China, Japan, Korea, Taiwan, Hong Kong, Macau, and Mongolia.22 Detailed search strategies are provided in the Supplementary Methods.

A comprehensive literature search was conducted from database inception to October 2025 in CINAHL, Embase, Global Health, PubMed, Scopus, and Web of Science. The search strategy combined controlled vocabulary and keywords related to older adults, SDM, barriers and facilitators, and East Asian healthcare systems. The strategy was developed with support from a health sciences librarian and iteratively refined to ensure comprehensive retrieval. The search was limited to English-language publications. Studies were excluded if their primary aim was to evaluate the effectiveness of a specific intervention without addressing barriers or facilitators of SDM. Non-original research articles, including conference abstracts, study protocols, reviews, commentaries, and instrument development studies, were also excluded. Search results were imported into Covidence, where duplicates were removed prior to screening. Two reviewers (SL and MH) independently screened titles and abstracts, followed by full-text reviews to determine eligibility. Discrepancies were resolved through discussion.

Data were extracted using a piloted data-charting form. Extracted information included bibliographic details, study aim, design, setting, participant characteristics, decision-making focus, conceptualization of SDM, and reported barriers and facilitators related to SDM. The data were synthesized descriptively using a deductive approach, with barriers and facilitators categorized into stakeholder domains, including patients, caregivers, clinicians, and health system factors. This categorization reflects a multilevel perspective on healthcare decision-making, consistent with prior research examining barriers and facilitators to SDM across multiple levels.12 Within each domain, findings were synthesized to capture the range of reported barriers and facilitators across studies.