P42.05
Background: Limited data exists on the effect of tenofovir on bone mineral density (BMD) in HIV negative women. This is a major concern for long-term PrEP regimens. We evaluated effects of daily oral tenofovir (TDF) and Truvada (FTC/TDF) compared to placebo on BMD among women in a substudy of the VOICE trial.
Methods: HIV negative women in Uganda and Zimbabwe on oral TDF, FTC/TDF, or placebo had BMD measurements of lumbar spine and total hip via dual energy x-ray absorptiometry (DXA) at baseline (BL) and every 24 weeks (w) until 48 w after study product completion. Plasma tenofovir levels were assessed every 12 w for the first 48 w. Student's t-test and regression models were used to compare the mean percentage (%) change from BL in hip and spine BMD between the active and placebo arms.
Results: Of 518 women enrolled, 432 (155 Uganda, 277 Zimbabwe) with DXA results at both BL and w 48 entered this analysis. Median age and BMI at BL were 28 years and 24.6 kg/m2. History of depot medroxyprogesterone acetate (DMPA) use was reported by 123 (28%) and 94% had moderate to high BL physical activity levels. In the primary analysis, there were no significant differences between arms in hip or spine BMD % change, likely due to low product use in VOICE. Tenofovir was detected in 75–100% of plasma samples in 43/118 (36%) TDF and 50/156 (32%) FTC/TDF recipients (median 4 samples tested). In these women, mean % change from BL to w 48 in spine BMD was 1.0% to 1.3% lower than placebo and hip BMD was 0.5% to 0.8% lower after adjusting for country, age, BMI, physical activity level, and history of DMPA use (p<0.05 for FTC/TDF and for oral active arms combined, but not TDF). BMD increased after stopping product; 48 w change was 0.6–1.2% higher in TDF and FTC/TDF vs placebo recipients.
Conclusions: Small but significant reversible decreases in BMD were observed among young African women with higher adherence on TDF-based oral PrEP. The observed differences were in the range seen in prior studies of HIV-negative men and women.
