Predictors of adherence to prescribed exercise programs for older adults with non-musculoskeletal indications for exercise: a systematic review

BACKGROUND AND OBJECTIVES: Prescribed exercise to treat medical conditions and to prepare for surgery is a promising intervention to prevent adverse health outcomes for older adults; however, adherence to exercise programs may be low. Our objective was to identify and grade the quality of predictors of adherence to prescribed exercise in older adults. METHODS After registration (CRD42018108242), prospective experimental studies were identified using a peer-reviewed search strategy applied to MEDLINE, EMBASE, Cochrane and CINAHL from inception until April 23, 2019. Following independent and duplicate review of titles, abstracts and full texts, we included prospective studies with an average population age ≥ 65 years, where exercise was formally prescribed for a medical or surgical condition. We excluded studies where exercise was prescribed for a chronic musculoskeletal condition. Risk of bias was assessed using the Quality in Prognostic studies tool or Cochrane risk of bias tool, as appropriate. Predictors of adherence were identified, pooled, and graded for quality using an adaptation of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework for predictor studies. RESULTS We included 19 observational studies and 4 randomized controlled trials (n = 5785) Indications for exercise included cardiac (n = 6), pulmonary rehabilitation (n = 7), or other (n = 10; surgical, medical, and neurologic). Overall adherence rate was reported in 20 studies (range 21%-93%; mean 68%, standard deviation 23%). Moderate-quality evidence suggested that positive predictors of adherence were self-efficacy and good self-rated mental health; negative predictors were depression (high quality) and distance from the exercise facility. Moderate-quality evidence suggested that comorbidity and age were not predictive of adherence. CONCLUSIONS These findings can inform design of future exercise programs as well as identification of individuals who may require extra support to benefit from prescribed exercise.