A systematic review and meta-analysis of adherence to physical activity interventions among three chronic conditions: cancer, cardiovascular disease, and diabetes

BACKGROUND: Physical activity is effective for the prevention and treatment of chronic disease, yet insufficient evidence is available to make comparisons regarding adherence to aerobic physical activity interventions among chronic disease populations, or across different settings. The purpose of this review is to investigate and provide a quantitative summary of adherence rates to the aerobic physical activity guidelines among people with chronic conditions, as physical activity is an effective form of treatment and prevention of chronic disease. METHODS: Randomized controlled (RCTs) trials where aerobic physical activity was the primary intervention were selected from PsychInfo, PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Clinical Key, and SCOPUS from 2000 to 2018. Studies were included if the program prescription aligned with the 2008 aerobic physical activity guidelines, were at least 12 weeks in length, and included adult participants living with one of three chronic diseases. The data was extracted by hand and the PRISMA (preferred reporting items for systematic review and meta-analysis) guidelines were used to evaluate risk-of-bias and quality of evidence. Data were pooled using random-effect models. The primary outcome measure was program adherence and the secondary outcome measures were dropout and setting (e.g. home vs. clinic-based). Pooled effect sizes and 95% CiIs (confidence intervals) were calculated using random-effect models. RESULTS: The literature search identified 1616 potentially eligible studies, of which 30 studies (published between 2000 and 2018, including 3,721 participants) met the inclusion criteria. Three clinical populations were targeted: cancer (n = 14), cardiovascular disease (n = 7), and diabetes (n = 9). Although not statistically significant, adherence rates varied across samples (65, 90, and 80%, respectively) whereas dropout rates were relatively low and consistent across samples (5, 4, and 3%). The average adherence rate, regardless of condition, is 77% (95% CI = 0.68, 0.84) of their prescribed physical activity treatment. The pooled adherence rates for clinic-based and home-based programs did not differ (74% [95% CI, 0.65, 0.82] and 80% [95% CI, 0.65, 0.91], respectively). CONCLUSIONS: The current evidence suggests that people with chronic conditions are capable of sustaining aerobic physical activity for 3+ months, as a form of treatment. Moreover, home-based programs may be just as feasible as supervised, clinic-based physical activity programs.