BACKGROUND:
Insulin resistance and lipid changes are common after antiretroviral therapy (ART) initiation. Observational studies suggest that vitamin D supplementation reduces the risk of developing diabetes and improves lipid profiles.

METHODS:
This 48-week prospective, randomized, double-blind, placebo-controlled study evaluated high-dose vitamin D3 (4000 IU daily) plus calcium supplementation (1000 mg calcium carbonate daily) in HIV-infected participants initiating ART with efavirenz/emtricitabine/tenofovir (EFV/FTC/TDF). Changes in insulin resistance (as estimated by homeostatic model assessment), fasting lipid profile, and components of the metabolic syndrome were assessed at baseline, 24 weeks, and 48 weeks. Stratified Wilcoxon rank sum tests and stratified normal score tests were used to evaluate differences between treatment arms, stratified by screening 25-OH vitamin D stratum (≤/>20 ng/mL).

RESULTS:
A total of 165 participants enrolled: 79 in the vitamin D/calcium (Vit D/Cal) arm and 86 in the placebo arm. Only the placebo arm experienced a modest increase in insulin resistance at week 24 (P < .001). While increases in total and high-density lipoprotein cholesterol were significant in both arms at weeks 24 and 48, increases in low-density lipoprotein cholesterol at week 24 were only identified in the placebo arm (P = .011). Body mass index remained stable, whereas modest increases in waist circumference were observed in the placebo arm. Metabolic syndrome was present in 19 participants (12%) at baseline and 20 participants (14%) at week 48, without differences between arms.

CONCLUSIONS:
Vit D/Cal supplementation over 48 weeks did not alter the lipid profile or glucose metabolism experienced with initiation of EFV/FTC/TDF in ART-naïve persons. Vitamin D supplementation is unlikely to be an effective strategy to attenuate metabolic dysregulations with ART initiation.