Objectives: Whether zidovudine (AZT)-associated lipoatrophy occurrence differs by concomitant exposure to protease (PIs) or non-nucleoside reverse transcriptase inhibitors (NNRTIs) remains unclear. Baseline body composition data from a randomized trial in subjects stable on first-line AZT-based therapy were used to explore this issue.
Methods: In this substudy of the PREPARE trial, centrally read baseline whole-body dual energy x-ray aborptiometry (DXA) and single-slice abdominal CT scans were analyzed with respect to duration and type of prior AZT/lamivudine (3TC) combination antiretroviral therapy (cART), including by multivariate linear regression adjusted for age, gender, ethnicity, body mass index (BMI), and nadir CD4.
Results: DXA and CT, from 134 and 136 patients, respectively [87% male; 82% Caucasian; mean (SD) age, 45.6 years (10); BMI, 24.3 kg/m² (3.2)], were analyzed. Prior AZT/3TC cART exposure was 5.5 (2.2) years. Seventy-eight and 27 patients had concomitantly and exclusively used NNRTIs and PIs, respectively. AZT/3TC cART, AZT/3TC/NNRTI, and AZT/3TC/PI, respectively, were associated with the presence of a mean (95% CI) of 247 g (-438 to -56; P = .012), 267 g (-467 to -66; P = .010), and 216 g (-430 to -1.7; P = .048) less baseline limb fat per additional year of prior exposure. Although abdominal subcutaneous (SAT) adipose tissue was likewise less with longer AZT/3TC cART, this was only significant for AZT/3TC/ NNRTI but not AZT/3TC/PI. Visceral adipose tissue (VAT) amount was not clearly associated to prior treatment. Increased age and male gender were independently associated with lower limb fat and SAT, but more VAT.
Conclusions: Longer exposure to AZT/3TC, regardless of whether in combination with PI or NNRTI, as well as increased age and male gender are independently associated with lower limb fat mass.