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

•Vitamin D deficiency is common during critical illness.•Vitamin D deficiency is associated with increased mortality and infections.•Normalization of vitamin D concentration by supplementation improves immunity.•Ergocalciferol modestly improved 25-hydroxyvitamin D concentrations dose dependently.•A trend in increased prevalence of hypercalcemia warrants caution for use of ergocalciferol

ObjectiveThe 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.MethodsA retrospective cohort of critically ill patients with traumatic injuries and vitamin D deficiency (25-OH vitamin D <50 nmol/L) were given either 50 000 IU of liquid ergocalciferol weekly, twice weekly, or three times weekly while in the intensive care unit (ICU). Serum 25-OH vitamin D and ionized calcium concentrations were monitored weekly. Ergocalciferol therapy was stopped when the serum 25-OH vitamin D was >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.ResultsSixty-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 < 0.001). Serum 25-OH vitamin D concentrations improved from 36 ± 6, 40 ± 7, and 37 ± 6 nmol/L to 50 ± 15, 54 ± 21, and 62 ± 17 nmol/L, respectively, after 2 wk of ergocalciferol therapy (P < 0.001) Two (13%), one (6%), and seven (23%) patients developed hypercalcemia for each dosage group, respectively (P = NS).ConclusionsErgocalciferol 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.