Therapeutic Quality Affects Physical Fitness Benefits of Home Exercise Interventions in Older Adults: A Systematic Review, Meta-Analysis, and Meta-Regression

BACKGROUND AND PURPOSE: The international Consensus on Therapeutic Exercise aNd Training (i-CONTENT) tool is a new instrument developed to evaluate the therapeutic quality of exercise interventions. Home-based exercise has been shown to improve physical fitness in older adults, but its effects may be influenced by therapeutic quality. The purpose of this systematic review was to describe the therapeutic quality of home-based exercise interventions for community-dwelling older adults and examine the relationship between therapeutic quality and changes in physical fitness. METHODS: Six electronic databases and 2 clinical trial registries were searched for randomized controlled trials investigating the effects of home-based exercise on physical fitness in community-dwelling older adults (≥60 years). Therapeutic quality was evaluated using the i-CONTENT tool for items of patient selection, type of exercise, safety, type/timing of outcomes, exercise dose, and adherence. International Consensus on Therapeutic Exercise aNd Training items were used to explain heterogeneity in meta-regression analyses. Risk of bias, certainty of evidence and credibility of analyses were assessed. RESULTS: Thirty-six trials (n = 6157 participants) were identified. Most studies (≥66.7%) had high or probably high therapeutic quality for i-CONTENT items, except exercise dose (47.2%) and adherence (16.7%). Interventions improved upper- (N = 20 trials; standardized mean difference [SMD] = 0.39; 95% CI, 0.13-0.64; low certainty of evidence) and lower-body strength (N = 28; SMD = 0.42; 95% CI, 0.08-0.77; very low certainty), and aerobic fitness (N = 8; SMD = 0.42; 95% CI, 0.08-0.77; very low certainty). For exercise dose, low- or probably low-quality studies negatively influenced effects on upper- (estimated β = -.48; P = .049; moderate credibility) and lower-body strength (estimated β = -.77; P = .048; moderate credibility). For adherence, low- or probably low-quality studies negatively influenced effects on aerobic fitness (estimated β = -.97; P = .02; low credibility). CONCLUSIONS: Home-based exercise may improve upper- and lower-body strength, as well as aerobic fitness in older adults. However, the effectiveness of interventions is affected by inadequate dosing of exercise programs and adherence issues. Physical therapists should have the best available evidence to support their clinical decision making, especially when designing and monitoring home programs.