Association between initiation of antiretroviral therapy with efavirenz and decreases in 25-hydroxyvitamin D.

BACKGROUND We aimed to determine whether antiretroviral therapy (ART) initiation with efavirenz (EFV) is associated with decreases in 25-hydroxyvitamin D (25[OH]D) compared with non-EFV regimens. METHODS 25(OH)D was measured from stored plasma samples in 87 ART-naive HIV-positive patients prior to ART initiation with EFV-containing (n=51) or non-EFV-containing (89% with protease inhibitors; n=36) regimens from a single clinic in Cleveland (OH, USA). A repeat measurement was made 6-12 months after ART initiation. The change in 25(OH)D after ART initiation and the prevalence of patients with hypovitaminosis D (< or = 37.5 nmol/l [15 ng/ml]) after ART initiation was compared in those who initiated ART with and without EFV using multivariable linear and modified Poisson regression, respectively. RESULTS Prior to ART initiation, the median (interquartile range [IQR]) 25(OH)D concentration was 52.7 nmol/l (IQR 32.2-72.1), with 33% prevalence of hypovitaminosis D. After 6-12 months of ART, 25(OH)D decreased by a mean +/-se of -12.7 +/-3.7 nmol/l in the EFV group relative to the non-EFV group (P=0.001) after adjustment for baseline 25(OH)D concentration, race and season (non-summer versus summer) at the visit 6-12 months after ART initiation. Similarly, after multivariable adjustment, the risk of hypovitaminosis D after ART initiation was significantly higher in the EFV group compared with the non-EFV group (prevalence ratio 1.8 [95% confidence interval 1.2-2.8]; P=0.007). CONCLUSIONS ART initiation with EFV is associated with significant decreases in 25(OH)D and an increased risk of hypovitaminosis D compared with non-EFV regimens.