Changes in Bone Mineral Density and Bone Turnover Markers in Antiretroviral Therapy-Naïve People with HIV Starting Bictegravir/Emtricitabine/Tenofovir Alafenamide or Doravirine/Lamivudine/Tenofovir Disoproxil Fumarate

Antiretroviral therapy (ART), including tenofovir disoproxil fumarate (TDF), has been associated with an increased risk of bone loss in people living with HIV (PLWH) compared with tenofovir alafenamide (TAF). However, there is no direct comparison about changes in bone mineral density (BMD) between the initial fixed-drug combination bictegravir/emtricitabine/TAF (BIC/F/TAF) and doravirine/lamivudine/TDF (DOR/3TC/TDF). A retrospective, observational, cohort study was conducted of PLWH aged >40 years who started an initial ART, including BIC/F/TAF or DOR/3TC/TDF, and underwent dual-energy X-ray absorptiometry (DXA) before ART initiation. BMD changes and variations in bone turnover markers (bone alkaline phosphatase and beta-crosslaps) were evaluated in participants who had follow-up DXA scans after ≥12 months of ART. As a whole, 72 persons (61 males, mean age 48.6 years) were enrolled: 39 starting BIC/F/TAF and 33 DOR/3TC/TDF. At baseline, 13 subjects (18%) were diagnosed with low BMD (T-score < −1.0 or Z-score < −2.0), without significant differences between groups. After a median follow-up of 14.3 months, decreases in median absolute BMD were comparable between groups. The median reduction (IQR) in BMD at the femur neck was −0.03 (−0.07, 0.00) g/cm ² in the BIC/F/TAF group and −0.04 (−0.08, −0–01) g/cm ² in DOR/3TC/TDF group ( p = .177). The median change (IQR) in BMD at the lumbar spine was −0.04 (−0.08, 0.00) g/cm ² in BIC/F/TAF group and −0.05 (−0.09, −0–01) g/cm ² in the DOR/3TC/TDF group ( p = .245). Changes in bone turnover markers were also comparable between groups. In our study, initial antiretroviral regimen with BIC/F/TAF or DOR/3TC/TDF caused comparable reduction in BMD and similar changes in bone turnover markers.