Associations between Tenofovir Diphosphate in Dried Blood Spots, Impaired Physical Function, and Fracture Risk

Abstract

Background: In this study, we evaluate associations between cumulative antiretroviral adherence/exposure, quantified using tenofovir diphosphate (TFV-DP) in dried blood spots (DBS), and human immunodeficiency virus (HIV)-related aging factors. Methods: This is a cross-sectional analysis of younger (ages 18-35) and older (ages ≥60) persons with HIV (PWH) taking TFV disoproxil fumarate. Tenofovir diphosphate concentrations were quantified in DBS. Linear and logistic regression models were used to evaluate associations between TFV-DP and bone mineral density (BMD), physical function, frailty, and falls. Results: Forty-five PWH were enrolled (23 younger, 22 older). Every 500 fmol/punch (equivalent to an increase in 2 doses/week) increase in TFV-DP was associated with decreased hip BMD (-0.021 g/cm2; 95% confidence interval [CI],-0.040 to-0.002; P=.03). Adjusting for total fat mass, every 500 fmol/punch increase in TFV-DP was associated with higher odds of Short Physical Performance Battery impairment (score ≤10; adjusted odds ratio [OR], 1.6; 95% CI, 1.0-2.5; P=.04). Every 500 fmol/punch increase in TFV-DP was associated with slower 400-meter walk time (14.8 seconds; 95% CI, 3.8-25.8; P=.01) and remained significant after adjusting for age, lean body mass, body mass index (BMI), and fat mass (all P≤.01). Every 500 fmol/punch increase in TFV-DP was associated with higher odds of reporting a fall in the prior 6 months (OR, 1.8; 95% CI, 1.1-2.8; P=.02); this remained significant after adjusting for age, lean body mass, BMI, and total fat mass (all P