A randomized controlled trial of vitamin D dosing strategies after acute hip fracture: no advantage of loading doses over daily supplementation.

Background: There remains uncertainty regarding the appropriate therapeutic management of hip fracture patients. The primary aim of our study was to examine whether large loading doses in addition to daily vitamin D offered any advantage over a simple daily low-dose vitamin D regimen for increasing vitamin D levels.

Methods: In this randomized controlled study, patients over age 50 with an acute fragility hip fracture were enrolled from two hospital sites in Ontario, Canada. Participants were randomized to one of three loading dose groups: placebo; 50,000 IU vitamin D2; or 100,000 IU D2. Following a placebo/loading dose, all patients received a daily tablet of 1,000 IU vitamin D3 for 90 days. Serum 25-hydroxy vitamin D (25-OHD) was measured at baseline, discharge from acute care (approximately 4-weeks), and 3-months.

Results: Sixty-five patients were enrolled in the study (44% male). An immediate rise in 25-OHD occurred in the 100,000 group, however there were no significant differences in 25-OHD between the placebo, 50,000 and 100,000 loading dose groups after 4-weeks (69.3, 84.5, 75.6 nmol/L, p = 0.15) and 3-months (86.7, 84.2, 73.3 nmol/L, p = 0.09), respectively. At the end of the study, approximately 75% of the placebo and 50,000 groups had reached the target therapeutic range (75 nmol/L), and 44% of the 100,000 group.

Conclusions: In correcting vitamin D insufficiency/deficiency in elderly patients with hip fracture, our findings suggest that starting with a lower daily dose of Vitamin D3 achieved similar results as providing an additional large loading dose of Vitamin D2. At the end of the study, all three groups were equally effective in attaining improvement in 25-OHD levels. Given that a daily dose of 1,000 IU vitamin D3 (with or without a loading dose) resulted in at least 25% of patients having suboptimal vitamin D status, patients with acute hip fracture may benefit from a higher daily dose of vitamin D.

Trial Registration: Clinical Trials # NCT00424619.