Abstract
BACKGROUND: Hypovitaminosis D can be observed in most fragility hip fracture patients. However, measurement of 25-hydroxyvitamin D (25(OH)D) level is costly and may not be available in some centers. Without the baseline serum 25(OH)D level, the appropriate dose of vitamin D supplementation is not known. The aim of this study was to evaluate the effectiveness and safety of vitamin D supplementation in fragility hip fracture patients compared between high- and low-dose vitamin D supplementation. METHODS: A total of 140 patients diagnosed with fragility hip fracture were randomly allocated to either the high-dose (60,000 IU/week) or low-dose (20,000 IU/week) vitamin D2 supplementation group for 12 weeks. The number of patients who achieved optimal vitamin D level (serum 25(OH)D > 30 ng/mL), the proportion of patients who developed hypercalcemia, and the functional outcome were compared between groups. RESULTS: Of the 140 patients who were enrolled, 21 patients were lost to follow-up during the study period. The remaining 119 patients (58 and 61 in the high- and low-dose groups, respectively) were included in the final analysis. The high-dose group had a higher rate of serum 25(OH)D restoration to optimal level than the low-dose group (82.8% vs 52.5%, respectively; p < 0.001). Approximately 3.4 and 1.6% of patients in the high- and low-dose groups, respectively, had mild transient hypercalcemia, but none developed moderate, severe, or symptomatic hypercalcemia. There were no differences in functional outcome scores between groups. CONCLUSIONS: In treatment settings where baseline serum 25(OH)D level can't be evaluated in older adults with fragility hip fracture, we recommend high-dose vitamin D2 of approximately 60,000 IU/week for 12 weeks, with subsequent switch to a maintenance dose. This regimen effectively restored serum vitamin D to an optimal level in 82.8% of patients without causing symptomatic hypercalcemia. TRIAL REGISTRATION: The protocol of this study was retrospectively registered in the Thai Clinical Trials Registry database no. TCTR20180302007 on 20 February 2018.