Vitamin D Deficiency May Be Associated with a More Rapid Decline in CD4 Cell Count to <350 Cells/µL in Untreated HIV-Infected Adults

Objectives: Low vitamin D status is associated with both increased disease progression and mortality in people with HIV receiving antiretroviral therapy (ART). However, data are lacking on effects of vitamin status on disease progression and CD4 cell count in people with HIV not receiving ART. We therefore evaluated effects of vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D] <50 nmol/L) on the decline in CD4 cell count in people with HIV not receiving ART. Methods: A retrospective cohort study including people with HIV not receiving ART and with an HIV viral load of >400 copies/mL. A proportional hazards model was fitted to evaluate the effect of vitamin D status on the time to decline in CD4 cell count (<350 cells/µL), adjusted for nadir CD4 cell count, time since HIV diagnosis, previous ART use and HIVviral load. Results: 224 participants fulfilled the inclusion criteria and were followed for a median of 11 months (range or IQR). At baseline, 42% had vitamin D deficiency and the median (interquartile range) CD4 cell count was 502 (355, 662) cells/µL. HIV-infected individuals with vitamin D deficiency had an increased risk of CD4 decline to <350 cells/µL [Hazard ratio (HR) 2.15 (95% CI 1.05, 4.38, p=0.04)]. Conclusion: Vitamin D deficiency was independently associated with an increased time to decline in CD4 cell count to <350 cells/µL, but not with a change in CD4 overall in people with HIV not receiving ART.