Predictors of participation in, adherence to and outcomes of cardiac rehabilitation in older adults: a scoping review

Background Cardiac rehabilitation lowers mortality and improves function, yet remains underused by older adults. Existing syntheses address access in general populations or frailty alone; none maps predictors across the whole pathway in later life. Aims To map reported predictors of participation, adherence and outcomes in older adults and identify evidence gaps. Methods Following JBI methodology and reported with PRISMA-ScR, eligibility used the Population, Concept, Context approach: older adults (mean or median age 65 years or older, or with extractable data for those aged 65 years or older) with a cardiovascular indication; any reported predictor of participation, adherence or outcomes; and any rehabilitation setting. MEDLINE (PubMed), the Cochrane Library, Europe PMC and DOAJ were searched from inception to July 2026, supplemented by grey literature and citation searching. Records were screened and charted in duplicate, with a third reviewer resolving disagreements. Critical appraisal was not undertaken. Results Of 5250 records screened, 366 studies were included; 356 yielded 1534 predictor associations. Evidence concentrated on outcomes (934) rather than participation (425) or adherence (175). Clinical (426) and sociodemographic (387) predictors predominated; psychosocial predictors were sparsest (173). Female sex and older age were the commonest barriers to participation. Functional and frailty-related predictors fell almost entirely in the outcome domain (209 of 236) and were rarely examined for participation (15) or adherence (12). Conclusions The evidence is extensive but unevenly distributed. Outcome prediction dominates, adherence is neglected, and frailty is studied as a determinant of outcome rather than access. Future work should address adherence and frailty as a predictor of participation. Registration Open Science Framework, https://doi.org/10.17605/OSF.IO/63TUK (PROSPERO does not register scoping reviews).