Low adherence to physical activity is associated with incident mobility in older adults with physical frailty and sarcopenia: results from the SPRINTT randomized clinical trial

Background: Physical activity (PA) and nutrition are the most effective strategies to prevent mobility disability and other negative outcomes in older adults. However, considerable heterogeneity was observed in response to PA across interventional studies. This may be explained by different levels of adherence to PA interventions among participants. Objectives: To examine the effects of adherence to a PA intervention on the risk of developing mobility disability in older adults with Physical Frailty and Sarcopenia (PF&S). Methods: Participants were community-dwelling older adults (70+ years) with PF&S enrolled in the SPRINTT trial (NCT02582138). PF&S was operationalized as having a total score from 3 to 9 at the Short Physical Performance Battery (SPPB), low appendicular lean muscle mass, and the ability to complete the 400 m walk test in <15 minutes. For the present investigation, data from participants allocated to the multicomponent intervention (PA plus nutrition) were analyzed. Adherence to PA was defined based on the number of weekly sessions attended and agreement with recommendations of the American College of Sports Medicine. Adherence was categorized as low (<2 sessions/week, LA), meeting recommendations (2–3 sessions/week, MR), and high recommendations (>3 sessions/week, AR). The primary outcome was incident mobility disability, operationalized as incident inability to complete the 400-m walk test in <15 minutes at follow-up. Results: 689 participants (mean age 79.3 years, 72.6% women) were included. In those with SPPB 3–7, MR [OR (95%CI): 0.56 (0.34, 0.93), p-value 0.025] and AR [OR (95%CI): 0.26 (0.16, 0.42), p-value <0.001] groups had lower risk of mobility disability compared to the LA group. In participants with SPPB 8–9, AR group had a significant lower likelihood of mobility disability comparing with the LA group [OR (95%CI): 0.18 (0.06, 0.57), p-value 0.004]. No significant differences were observed between MR and AR groups. Conclusion: In older adults with PF&S, a high adherence to PA recommendations is associated with reduced incidence of mobility disability.