Serum Vitamin D Level at ICU Admission and Mortality

Vitamin D is a fat-soluble vitamin that plays a major role in the regulation of bone and calcium metabolism and has effects on the immune and cardiovascular systems. Vitamin D deficiency is commonly seen in the general population as well as in critically ill patients and is reported to be associated with increased mortality and morbidity. Our aim was to determine the relationship between vitamin D level at ICU admission and mortality.

A total of 491 patients admitted to the ICU between January 2014 and January 2015 were evaluated retrospectively. The patients who were under 18 years old, had elective surgery, or whose serum vitamin D levels and outcomes were unknown were excluded. The patient's age, gender, APACHE II score, number of organ dysfunction, serum vitamin D level at ICU admission and outcomes were recorded.

Vitamin D level was low (<25 ng dL^-1) in 166 (77.1%) of the patients. In non-survivor patients, APACHE II score and the number of organ dysfunction were significantly higher than the survivor patients (p<0.001 and p<0.001). There was a negative correlation between vitamin D level and APACHE II score (r²=0.04, p=0.006). In multivariate analyses, the likelihood of mortality was increased 9.8-fold (range 4.2-17.6) and 8.9-fold (range 3.9-14.1) with an APACHE II score ≥24 and the number of organ dysfunction ≥2, respectively (p<0.001 and p<0.001).

Vitamin D deficiency is commonly seen in intensive care patients. Although it is not an independently decisive factor for mortality, it might be related with poor clinical status at ICU admission. The APACHE II score and number of organ dysfunction are still important parameters for increased mortality.