[Severe 25-OH vitamin D deficiency in patients on chronic hemodialysis]

25-OH vitamin D deficiency is associated with increased cardiovascular mortality in general population and in chronic kidney disease. The aim of this study was to evaluate 25-OH-Vitamin D (25-D) serum levels in chronic hemodialysis (HD) patients and its relationship with cardiovascular and non-cardiovascular risk factors.

We performed a cross-sectional study with 187 prevalent HD patients (106 M/ 81 F) in chronic hemodialysis. 25-D were measured in January and blood samples were collected for analysis before a midweek HD session.

The mean age of patients was 67 15 years with the mean HD time of 73 68 months. Forty-six patients (25%) were diabetics. 31% of the patients were taking i.v. paricalcitol and 22% were taking calciomimetics. None of patients were receiving native vitamin D. Serum levels of 25-OH-Vitamin D were low (11,77,5 ng/ml). Only 4% of patients had values of 25- OH-Vitamin D considered normal by the guidelines KDOQI. Levels of 25-D were deficient and insufficient respectively in 73% and 23% of the patients. In univariate analysis, serum levels of 25-D were negatively correlated with female sex and diabetes and positively correlated with albumin. In multivariate analysis dialysis vintage, lower serum calcium, hypoalbuminemia, higher BMI and treatment with paricalcitol were independently associated with lower levels of 25-OH-Vitamin D. Deficiency of 25-D is extremely common in chronic hemodialysis. It is still to be investigated by randomized prospective studies if native vitamin D supplementation is able to improve clinical outcomes in dialysis.