Effectiveness of physical activity interventions in older adults with frailty or prefrailty: a systematic review and meta-analysis

Background: Physical activity is known to prevent frailty and reduce its consequences; however, it remains unclear which interventions are optimal for older adults with frailty. We conducted a systematic review and meta-analysis to identify effective physical activity interventions in improving outcomes related to frailty. Methods: We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials and CINAHL (inception to July 2019) for English-language randomized controlled trials (RCTs) of physical activity interventions in adults aged 65 years or more who were prefrail or frail; we included observational and cohort studies when there were no RCT data. Outcomes of interest were frailty, mobility, physical function, cognitive function, use of health care services and quality of life. After data extraction, we assessed the risk of bias using the Cochrane Collaboration risk of bias tool for RCTs and the Newcastle–Ottawa Scale for observational studies, rated the certainty of evidence with the Grading of Recommendation, Assessment, Development and Evaluations (GRADE) approach, and assessed statistical and methodologic heterogeneity. Results: We identified 26 studies (24 RCTs [1 of which did not have any relevant outcomes for extraction] and 2 observational studies) involving 8022 prefrail or frail older adults. Nine studies had low risk of bias, 2 had high risk of bias, and for 13 the risk of bias was unclear. The trials included mixed (aerobic and muscle-strengthening) (n = 13), muscle-strengthening (n = 8), mobilization and rehabilitation (n = 4) or aerobic (n = 1) activities. Significant effects were found for mobility (standardized mean difference [SMD] 0.60, 95% confidence interval [CI] 0.37 to 0.83), activities of daily living (SMD 0.50, 95% CI 0.15 to 0.84), cognitive function (SMD 0.35, 95% CI 0.09 to 0.61), quality of life (SMD 0.60, 95% CI 0.13 to 1.07) and frailty (SMD −1.29, 95% CI −2.22 to −0.36; risk ratio 0.58, 95% CI 0.36 to 0.93), with moderate certainty of evidence. Interpretation: There is low-to moderate-level evidence that various physical activity interventions are beneficial for prefrail and frail older adults. Studies need to better define frailty to ensure the identification and implementation of such interventions into clinical practice. PROSPERO registration: CRD42020144556