Patterns of objectively measured physical activity differ between men living with and without HIV

Abstract

Objective: To use accelerometers to quantify differences in physical activity (PA) by HIV serostatus and HIV viral load (VL) in the Multicenter AIDS Cohort Study (MACS).

Methods: MACS participants living with (PLWH, n = 631) and without (PWOH, n = 578) HIV wore an ambulatory electrocardiogram monitor containing an accelerometer for 1-14 days. PA was summarized as cumulative mean absolute deviation (MAD) during the 10 most active consecutive hours (M10), cumulative MAD during the six least active consecutive hours (L6), and daily time recumbent (DTR). PA summaries were compared by HIV serostatus and by detectability of VL (>20 vs. ≤20 copies/ml) using linear mixed models adjusted for sociodemographics, weight, height, substance use, physical function, and clinical factors.

Results: In sociodemographic-adjusted models, PLWH with a detectable VL had higher L6 (β = 0.58 mg, P = 0.027) and spent more time recumbent (β = 53 min/day, P = 0.003) than PWOH. PLWH had lower M10 than PWOH (undetectable VL β = -1.62 mg, P = 0.027; detectable VL β = -1.93 mg, P = 0.12). A joint test indicated differences in average PA measurements by HIV serostatus and VL (P = 0.001). However, differences by HIV serostatus in M10 and DTR were attenuated and no longer significant after adjustment for renal function, serum lipids, and depressive symptoms.

Conclusions: Physical activity measures differed significantly by HIV serostatus and VL. Higher L6 among PLWH with detectable VL may indicate reduced amount or quality of sleep compared to PLWH without detectable VL and PWOH. Lower M10 among PLWH indicates lower amounts of physical activity compared to PWOH.

Figure 1:. Illustration of L6 and M10 for One Participant

The timeseries represents one individual’s minute-wise average mean absolute deviation of the vector magnitude of acceleration (MAD) across fourteen days of wear. Units are mili-gravitational units (g=9.801 m/s²). The timeseries demonstrates a typical diurnal activity pattern for a human subject: highest in the morning, lower in the afternoon, and lowest in the evening and through the night. The left-most box represents the 6 hours with the lowest physical activity (L6) and the right-most box the 10 hours with the highest physical activity (M10). The widths of the boxes are six and ten hours, respectively. The heights of the boxes represent the average MAD for L6 and M10. This individual was least active from roughly 1:30 to 7:30 and was most active from roughly 9:00 to 19:00.

Figure 2:. Pairwise Scatterplots and Pearson Correlations of Activity Measurements

Across 1,209 participants in the MACS with activity summaries, only small correlations (ρ) were observed between ten-hour highest daily vector magnitude counts (M10), six-hour lowest daily vector magnitude counts (L6), and daily time spent resting recumbent (DTR).