Vitamin D assessment over 48 weeks in treatment-naive HIV individuals starting lopinavir/ritonavir monotherapy

Background: Vitamin D deficiency is common in HIV population and has been associated with increased comorbidity risk and poor immunologic status. Objective: To evaluate the effect of protease inhibitor lopinavir/ritonavir monotherapy on changes in serum 25-hydroxyvitamin D [25(OH)D] over 48 weeks. Methods: Thirty-four treatment-naïve HIV individuals initiating lopinavir/ritonavir monotherapy and receiving clinical care from private practice in Houston, Texas, were included. Serum 25-hydroxyvitamin D levels from stored plasma samples collected from IMANI-2 pilot study at both baseline and 48 weeks were analyzed using LC-MS assays. Mean 25(OH)D at baseline and 48 weeks were compared using paired t-tests. Linear regression analysis was used to evaluate factors associated with changes in 25(OH)D. Logistic regression analyses were used to determine the effect of vitamin D status and covariates on CD4 cell count recovery. Results: Mean 25(OH)D was significantly higher at 48 weeks (26.3 ng/mL (SD ± 14.9); p=0.0003) compared to baseline (19.8 ng/mL (SD ± 12.1), with fewer individuals having vitamin D deficiency (41.2%) and severe deficiency (11.8%). Both body mass index and baseline CD4 cell count were significant independent covariates associated with 25(OH)D changes over 48 weeks. Baseline vitamin D status did not affect CD4 cell count recovery. However, in a 24-week multivariate analysis, current tobacco use was significantly associated with a decreased odds of CD4 cell count recovery (AOR 0.106, 95% CI 0.018-0.606; p=0.012). Conclusion: Individuals treated with lopinavir/ritonavir monotherapy had significantly higher 25(OH)D after 48 weeks. Current tobacco users had significantly diminished CD4 cell count recovery after starting treatment, warranting further clinical investigation.