Approximately one-third of the US population is at risk of or already deficient in vitamin D, defined as a serum 25-hydroxyvitamin D level <50 nmol/L. Low 25-hydroxyvitamin D is prevalent in the HIV-infected population, and may be associated with increased risk of disease progression.
A study published in a recent issue of the Journal of Acquired Immune Deficiency Syndromes demonstrates that low baseline vitamin D deficiency may decrease the effectiveness of rosuvastatin in adults with HIV.
The research group analyzed serum 25-hydroxyvitamin D concentrations from SATURN-HIV, a randomized placebo, controlled trial evaluating the effects of rosuvastatin in adults with HIV.  They investigated whether rosuvastatin affected serum vitamin D levels over time, and if vitamin D status modified rosuvastatin’s effects.
They compared 25-hydroxyvitamin D levels at baseline and at the end of the study period between the placebo and rosuvastatin groups. Changes in vitamin D levels, regardless of baseline status, were not significant, suggesting that rosuvastatin does not have an effect on vitamin D. 
However, baseline vitamin D deficiency (defined in this study as <20 ng/mL) negatively impacted rosuvastatin’s beneficial effects on both cardiovascular and immune-activation endpoints, showing either weakened or unapparent effectiveness overall. This was seen in changes in LDL-cholesterol, lipoprotein-associated phospholipase A2, and common carotid artery intimal media thickness. The researchers also noted changes in the proportion of patrolling monocytes, a subset of monocytes that patrol healthy tissues by long-range crawling on the resting endothelium.
Findings from this analysis suggest that rosuvastatin administration does not improve vitamin D levels. However, individuals with baseline vitamin D deficiencies may experience diminished rosuvastatin effectiveness.
The researchers concluded that vitamin D supplementation may be necessary when initiating statin therapy in HIV patients who are deficient at baseline. 

Hileman C, Tangpricha V, Sattar A, McComsey G. Baseline vitamin D deficiency decreases the effectiveness of statins in HIV-infected adults on antiretroviral therapy. JAIDS Journal of Acquired Immune Deficiency Syndromes. 2016; doi:10.1097/qai.0000000000001281.