A Randomized Study of a Single Dose of Intramuscular Cholecalciferol in Critically Ill Adults

Priya Nair, Bala Venkatesh, Paul Lee, Stephen Kerr, Dominik J. Hoechter, Goce Dimeski, Jeffrey Grice, John Myburgh, Jacqueline R. Center

To determine the effect of two doses of intramuscular cholecalciferol on serial serum 25-hydroxy-vitamin-D levels and on pharmacodynamics endpoints: calcium, phosphate, parathyroid hormone, C-reactive protein, interleukin-6, and cathelicidin in critically ill adults. Prospective randomized interventional study. Tertiary, academic adult ICU. Fifty critically ill adults with the systemic inflammatory response syndrome. Patients were randomly allocated to receive a single intramuscular dose of either 150,000 IU (0.15 mU) or 300,000 IU (0.3 mU) cholecalciferol. Pharmacokinetic, pharmacodynamic parameters, and outcome measures were collected over a 14-day period or until ICU discharge, whichever was earlier. Prior to randomization, 28 of 50 patients (56%) were classified as vitamin D deficient. By day 7 after randomization, 15 of 23 (65%) and 14 of 21 patients (67%) normalized vitamin D levels with 0.15 and 0.3 mU, respectively (p = 0.01) and by day 14, 8 of 10 (80%) and 10 of 12 patients (83%) (p = 0.004), respectively. Secondary hyperparathyroidism was manifested in 28% of patients at baseline. Parathyroid hormone levels decreased over the study period with patients achieving vitamin D sufficiency at day 7 having significantly lower parathyroid hormone levels (p < 0.01). Inflammatory markers (C-reactive protein and interleukin-6) fell significantly over the study period. Greater increments in 25-hydroxy-vitamin-D were significantly associated with greater increments in cathelicidin at days 1 and 3 (p = 0.04 and 0.004, respectively). Although in-hospital mortality rate did not differ between the groups, patients who did not mount a parathyroid hormone response to vitamin D deficiency had a higher mortality (35% vs 12%; p = 0.05). No significant adverse effects were observed. A single dose of either dose of intramuscular cholecalciferol corrected vitamin D deficiency in the majority of critically ill patients. Greater vitamin D increments were associated with early greater cathelicidin increases, suggesting a possible mechanism of vitamin D supplementation in inducing bactericidal pleiotropic effects.