The BMD Substudy was an observational substudy of VOICE designed to assess the impact of oral TDF and oral FTC/TDF on bone mineral density. VOICE participants randomized to oral study product at MTN-003B study sites were offered participation in the BMD Substudy (518 of 567 eligible VOICE participants enrolled in MTN-003B). Scheduled follow-up, including nutritional assessment, DXA scan, and blood tests related to bone turnover and metabolism, occurred on a semi-annual basis during VOICE study participation, at the scheduled end of product use visit, and (with the protocol amendment in August 2011) at 12 months following the discontinuation of an oral study product in VOICE.
A secondary objective of the study was to provide a description of changes over time in nutritional assessment components among eligible VOICE participants. Exploratory objectives include the examination of potential mechanisms of BMD changes among eligible VOICE participants, as well as changes in urinary phosphorous excretion in relation to possible changes in bone density. The potential impact of tenofovir-containing prevention agents on the bone density of healthy women of reproductive age, who may be exposed to other possible stressors on bone health, will be important for the evaluation of the overall safety of these agents for prevention of HIV infection in women.
Primary study results were presented at the HIV Research for Prevention (HIV R4P) meeting held October 28-31, 2014 in Cape Town, South Africa. The baseline manuscript is in press.
Observational substudy of VOICE