Evaluation of vitamin D endocrine system (VDES) status and response to treatment of patients in intensive care units (ICUs) using an on-line SPE-LC-MS/MS method.

Vitamin D deficiency is recognized as one of the most common chronic medical conditions in the world. Vitamin deficiency has been associated with increased mortality. The aim of the study here presented was to evaluate the vitamin D endocrine system (VDES) status in healthy blood donors and critically ill patients baseline and in response to treatment during a week with two doses of 1.5 mg of 25-hydroxyvitamin D3 and 2 microg calcitriol (1,25(OH)2D3) IV on alternate days, by monitoring levels in serum of major vitamin D metabolites in critically ill patients. Group 1: healthy blood donors (control group) (n=92), and group 2: critically ill subjects from an intensive care unit (ICU) (n=33). Critically ill patients were divided into three groups: group A (n=12) is the control group; group B (n=11), administration PO 1,5 mg of 25(OH)D3, in days 0 and 4 of treatment; and group C (n=11), administration IV of 2 microg 1,25(OH)2D3 on alternate days. Baseline serum levels of vitamin D2 and 25(OH)D2 were not detected. Vitamin D3 (9.8 vs 26.0 nM) (p<0.05), 25(OH)D3 (13.3 vs 52.3 nM) (p<0.001), and 1,25(OH)2D3 (53.8 vs 120.5 pM) (p<0.01) serum levels were significantly lower in critically ill subjects than in healthy donors. After treatment in group B: 25OHD3 increased to 46.0+/-16.5 ng/ml (p<0.0001) (22.2%<75 nM, 11.1% <50 nM). 1,25(OH)2D3 increased to 121.8+/-61.8 pM<0.01 whereas were slightly decreased in the other groups during the study. 24,25(OH)2D3 serum levels were increased in patients treated with calcitriol 8.5+/-5.3 vs 24.8+/-16.3 nM (p<0.05) while the levels kept stable in group A patients. In summary, critically ill patients have a severe vitamin D deficiency, which can be easily corrected by administration of high doses of 25OHD (PO). The VDES functional deficiency could be probably also corrected through administration of calcitriol (IV). Both treatments could produce an improvement in the general health and probably a reduction in overall mortality risk of the critically ill patients.