Supraphysiological 25-hydroxy vitamin D3 level at admission is associated with illness severity and mortality in critically ill patients

Ravikar Ralph, John Victor Peter, Anugrah Chrispal, Anand Zachariah, Joseph Dian, Tunny Sebastian, Bala Venkatesh, Kurien Thomas

We studied the association between admission serum 25-hydroxy vitamin D3 level and in-hospital mortality in a prospective cohort of critically ill patients admitted to the medical intensive care unit of a tertiary care referral center. Of the 180 patients enrolled, 129 were included. Vitamin D3 deficiency was observed in 37 % (n = 48) and supra-physiological levels (≥250 nmol/L) in 15.5 % (n = 20). Patients with supraphysiological vitamin D3 levels were grouped as outliers. There was no difference in mortality (p = 0.41) between vitamin D3 deficient (21/48) and non-deficient (36/81) patients in analysis with and without outliers. Patients with vitamin D3 ≥250 nmol/L had a significantly higher (p = 0.02) Simplified Acute Physiology Score (SAPS) II and mortality (p = 0.003) [mean (SD) 60.1 ± 17.1 and 75 % (15/20), respectively] when compared with the rest [45.6 ± 18 and 38.5 % (42/109), respectively]. The sensitivity, specificity and SAPS II independent odds ratio to predict mortality in patients with supraphysiological vitamin D3 levels were 26.3, 93.1 and 3.7 % (95 % confidence interval 1.2-11.4; p = 0.03), respectively. In conclusion, vitamin D3 deficiency in our cohort was not associated with mortality. A patient subset with supra-physiological vitamin D levels had higher illness severity scores and mortality. Extrinsic factors interfering with test results were ruled out. A biological hypothesis to explain this observation is proposed. Further clarification of mechanisms leading to this observation is warranted.