Dose-response effect of ergocalciferol therapy on serum 25-hydroxyvitamin D concentration during critical illness

Abstract Objective The aim of this study was to evaluate the dose–response relationship between ergocalciferol therapy and serum 25-hydroxyvitamin D concentrations in enterally fed, critically ill patients with traumatic injuries. Methods A retrospective cohort of critically ill patients with traumatic injuries and vitamin D deficiency (25-OH vitamin D  75 nmol/L, if the patient experienced hypercalcemia (ionized calcium >1.34 mmol/L), when the patient was discharged from the ICU, or if enteral nutrition was discontinued. Results Sixty-five patients (16, 18, and 31 per dosage group) were examined. One (6%), two (11%), and eight (26%) patients achieved normal 25-OH vitamin D concentrations after 2 to 4 wk of ergocalciferol therapy for each dosage group, respectively ( P P P = NS). Conclusions Ergocalciferol therapy improved baseline serum 25-OH vitamin D concentrations but was inadequate for consistently achieving normal serum concentrations of 25-OH vitamin D during critical illness. The trend in increasing appearance of mild hypercalcemia for the highest dosage group is concerning.