Endocrine Abstracts

Introduction: 25-Hydroxyvitamin D (25(OH)D) deficiency is a growing healthcare problem in HIV-infected patients. Evidence suggests that an optimal level of 25(OH)D would avoid secondary hyperparathyroidism but its optimal serum concentration has not been defined in HIV-infection. The aim of our study was to identify the 25(OH)D serum concentration that correlates to i-PTH increase and describe the prevalence of hypovitaminosis D in a cohort of HIV-infected patients.

Methods/designs: Cross-sectional study in HIV-infected subjects residing in the healthcare area of our Hospital’s area of reference located in Southern Spain. 25(OH)D status were defined as normal, deficiency or insufficiency according to criteria of EuroSIDA prospective study. Secondary hyperparathyroidism was defined if serum levels of i-PTH were ≥65 pg/ml in absence of other diseases related to calcium and/or vitamin D metabolism.

Results: 101 HIV-infected individuals were evaluated. Mean serum concentrations of 25(OH)D and i-PTH were 30.5±13.8 and 47.6±19.2 pg/ml respectively. 43.6% of the cohort was classified as having normal levels of 25(OH)D, 37.6% as insufficiency and 18.8% as deficiency. 13.9% patients had secondary hyperparathyroidism. There was a negative correlation between 25(OH)D levels and serum concentration of i-PTH (r=−0.28; P=0.005). 93% of the cases with an increased level of i-PTH had serum levels of 25(OH)D ≤28.5 ng/ml. On the ROC curve, the best sensitivity and specificity values were obtained if an optimal cut-off point for serum 25(OH)D, 21.4 ng/ml was used (area under curve: 84% and 95% CI 75–94%).

Conclusions: From a biological point of view, our results suggest that the normal ranges for our HIV-infected population could correspond to 25(OH)D levels ≥28.5 ng/ml, with a 93% of sensitivity to detect secondary hyperparathyroidism. The knowledge of these results could help us to decide which patients could be supplemented with vitamin D.