Muscle Quality and Physical Function in Men With and Without HIV.

BACKGROUND

People with HIV (PWH) experience faster physical decline than those without HIV (PWoH), despite antiretroviral therapy. We compared skeletal muscle density and area and their relationship with physical function among PWH and PWoH.

METHODS

Quantitative computed tomography scans were performed at the L4-L5 spinal region and the thigh to evaluate muscle groups in Multicenter AIDS Cohort Study participants at baseline. Using exploratory factor analysis, we summarized aggregated muscle measures based on factor loadings. Longitudinal associations between muscle area and density with gait speed and grip strength were examined using multivariable linear regression models with generalized estimating equations, adjusting for demographics, HIV serostatus, and other health metrics.

RESULTS

We included 798 men (61% of PWH). The median age was 54 years (interquartile range: 49-59), 61% were White, 32% Black, and 10% Hispanic. Among them, 22% had a body mass index over 30 kg/m2, and 14% had diabetes. Two factors emerged from the factor analysis explaining 55.9% of variance. Factor 1 (explained 32.5% of variance) encompassed all density measures. Factor 2 (explained 23.4% of variance) encompassed all area measures. Associations between muscle density and gait speed were more pronounced with aggregated measures than with individual ones. Specifically, each unit increase in overall muscle density correlated with a 0.028 m/s increase in gait speed (95% confidence interval [CI]: 0.017, 0.038, p < .01). Grip strength was associated with aggregated measures of both muscle density and area, with overall muscle density associated with a 1.88 kg increase in grip strength (95% CI: 1.29, 2.46, p < .01), and overall muscle area with a 1.60 kg increase (95% CI: 1.02, 2.19, p < .01).

CONCLUSIONS

Aggregated muscle density and area measurements were significantly associated with physical function. These correlations underscore the importance of interventions to enhance skeletal muscle to improve healthy aging for PWH and PWoH.