Obesity attenuates serum 25-hydroxyvitamin D response to cholecalciferol therapy in critically ill patients

Objectives: The presence of obesity may confound cholecalciferol dosing in vitamin D-deficient patients owing to potentially decreased bioavailability. The aim of this retrospective study was to evaluate cholecalciferol therapy in vitamin D-deficient, critically ill trauma patients with and without obesity. Methods: Adult patients with severe traumatic injuries who had a serum 25-hydroxyvitamin D (25-OH vit D) <50 nmol/L were prescribed 10 000 IU of liquid cholecalciferol daily. Efficacy was defined as achievement of a 25-OH vit D of 75 to 200 nmol/L. Safety was evaluated by the presence of hypercalcemia (serum ionized calcium >1.32 nmol/L). Fifty-three patients (18 obese, 35 non-obese) were identified for study. Results: Despite similar baseline concentrations (36 +/- 7 versus 37 +/- 7 nmol/L; P= NS), 25-OH vit D response was attenuated for those with obesity after 1 and 2 wk of cholecalciferol therapy (51 +/- 18 versus 66 +/- 27 nmol/L, P < 0.01; 68 +/- 19 versus 92 +/- 25 nmol/L, P < 0.01, respectively). Patients with obesity also tended to experience less hypercalcemia (22% versus 49% of patients, respectively) post-cholecalciferol therapy. Conclusion: Obesity alters the response to cholecalciferol therapy in critically ill patients with severe traumatic injuries. (C) 2019 Elsevier Inc. All rights reserved.