Prevalence of vitamin D deficiency in critically ill patients and its influence on outcome: experience from a tertiary care centre in North India (an observational study)

BACKGROUND: Limited studies are available on prevalence and severity of vitamin D deficiency in a critically ill population. To the best of our knowledge, this the first study of its kind in an Indian intensive care set-up. METHODS: One hundred fifty-eight critically ill patients were prospectively enrolled for over 2 years. Demographic profile and clinical characteristics were noted. Blood sample for serum 25 (OH) D was collected on admission (4 ml). Serum 25 (OH) D was measured using radioimmunoassay kit. Vitamin D deficiency was labelled as insufficient (31–60 nmol/l), deficient (15–30 nmol/l) and undetectable (<15 nmol/l). Statistical tests used were t test, chi-square test and binary logistic regression. RESULTS: Vitamin D deficiency (<60 nmol/l) was present in 127 patients (80.4%). Twenty-six patients had (20.47%) undetectable vitamin D levels. The mean vitamin D level was higher amongst survivors (43.17 + 39.22) than in non-survivors (39.72 + 29.31). Vitamin D was not significantly associated with mortality in univariate analysis. Multiple logistic regression showed admission APACHE II (p = 0.008), lactate (p = 0.013) and pre-ICU hospital stay (p = 0.041) as independent predictors of mortality in critically ill patients (p < 0.05). CONCLUSIONS: Vitamin D deficiency is highly prevalent in critically ill patients. A causal association between vitamin D deficiency and mortality was not found in our study. Larger studies are needed to understand the relationship between vitamin D deficiency and ICU outcome.