Are exercise benefits in older adults clinically meaningful?: An ancillary and follow-up analysis of a multicenter randomized controlled trial.

Physical exercise is beneficial for older adults, but little is known about inter-individual response variability or whether its effects reach clinical significance. We analyzed individual clinically meaningful responses to exercise in older adults. This is an ancillary analysis of a multicenter randomized controlled trial. 188 older patients (> 75 years) with mild cognitive impairment were randomly assigned to a 3-month home-based multicomponent exercise intervention (3-5 days/week based on Vivifrail program) or to a control group. Clinically meaningful responses were assessed for functional ability (≥ 5 points in Barthel Index) as well as for the locomotion (≥ 1 point in the short physical performance battery [SPPB]), cognition (≥ 3 points in the mini-mental state examination [MSSE]), psychology (≥ 2 points in the Geriatric Depression Scale [GDS]), and vitality domains (≥ 1 kg in handgrip strength) of intrinsic capacity. A total of 72 and 46 participants were included in the analyses for the control and intervention group, respectively. Most participants in the exercise group (89.1%) showed clinically meaningful responses to at least one outcome (OR = 4.82 [95%CI = 1.56-14.88], p = 0.006 vs. controls). Specifically, participants in the exercise group were more likely to respond to the SPPB than controls (67.4 vs 30.0%; OR = 5.05 [1.96-13.01]; p = 0.001), but no differences between groups were found for GDS, MMSE, handgrip strength, or Barthel Index (response rate for all < 40%, p > 0.05). In summary, a 3-month exercise intervention induces clinically meaningful benefits in most older adults, although these benefits are mostly restricted to the locomotion domain. Research is warranted to determine the individuals' and interventions' characteristics that maximize responsiveness.