Moderate-to-Vigorous Physical Activity, Muscle Function, and Contemporary Sarcopenia Definitions in Older Adults With HIV

Background: We examined associations between physical activity (PA), muscle function, and sarcopenia in older people with HIV (PWH). Setting: Multi-site PROSPER-HIV Study, including data from Seattle, WA, Cleveland, OH, and Birmingham, AL. Methods: In this cross-sectional study, we analyzed data from 148 PWH aged ≥50 years. Assessments included dual-energy X-ray absorptiometry for lean mass, handgrip strength, gait speed, chair stands, and Short Physical Performance Battery (SPPB). PA was objectively measured with ActiGraph accelerometers. Sarcopenia was defined using EWGSOP2, SDOC, and SDOC-HIV criteria. Regression models assessed associations between PA and sarcopenia, adjusting for age, sex, race, and body mass index. Results: Participants were 62.5 years old on average and 29.1% female. Sarcopenia prevalence varied widely: 1.4% under EWGSOP2, 4.1% under SDOC, and 15.2% under SDOC-HIV, with poor agreement across definitions (κ≤0.16). Participants presented a median of 105 minutes/week of moderate-to-vigorous PA (MVPA) and 4,123 steps/day. Higher MVPA was associated with lower odds of probable/confirmed sarcopenia using EWGSOP2 (OR=0.982; p <0.01). No significant associations were observed using SDOC or SDOC-HIV definitions (all p >0.05). MVPA was positively associated ( p <0.05) with handgrip strength and SPPB. Our fully adjusted model indicated that approximately 83 additional minutes of MVPA per week would be required to increase handgrip strength by 1 kg. Conclusion: Higher MVPA was associated with better muscle strength and physical performance, and with lower odds of probable/confirmed sarcopenia using EWGSOP2, whereas no significant associations were observed using SDOC or SDOC-HIV. These findings support further investigation of MVPA as a potentially important lifestyle strategy for maintaining muscle health in older PWH.