[2026-01-26] Vitamin D Deficiency and Bone Turnover in People Living With HIV Switching to Tenofovir Disoproxil Fumarate/Lamivudine/Dolutegravir Versus Continuing Nonnucleoside Reverse Transcriptase Inhibitor or Protease Inhibitor Regimens in Thailand

Abstract

Background: People living with HIV (PLWH) frequently have low bone mineral density, with vitamin D deficiency as a key risk factor. Recently, World Health Organization (WHO) and Thai national HIV guidelines recommend dolutegravir as first-line therapy, replacing nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen.

Objectives: To compare vitamin D levels and bone changes in PLWH switching from NNRTI- or boosted protease inhibitor (PI)-containing regimens to DTG-based therapy versus those continuing NNRTI- or PI-based therapy.

Methods: This post hoc analysis used data from a randomized controlled trial (2020-2022) at Suddhavej Hospital, a university-affiliated tertiary care hospital in Maha Sarakham, Thailand. PLWH aged 18 years or older without virologic failure were randomized to either continue current NNRTI/boosted PI-containing combined antiretroviral therapy (control group, CG) or switch to tenofovir disoproxil fumarate/lamivudine/dolutegravir (TDF/3TC/DTG) (switch group, SG). The primary outcome was vitamin D deficiency at 48 weeks; secondary outcomes assessing changes in bone metabolism markers.

Results: Thirty-nine patients completed follow-up (20 CG, 19 SG). After 48 weeks, vitamin D deficiency prevalence increased in both groups (CG: 15% to 35%; SG: 15.8% to 31.6%) with no significant difference (P = .905). Osteocalcin increased in SG but decreased in CG (P = .036). Beta-crosslaps increased in both groups (P = .461 between groups). Procollagen type 1 amino-terminal propeptide showed a nonsignificant decrease in both (P = .960).

Conclusions: Switching to TDF/3TC/DTG had minimal impact on vitamin D status but was associated with increased osteocalcin, suggesting a possible positive effect on bone formation. No significant differences were seen in bone resorption or other formation markers.