Serum levels of 25-hydroxyvitamin D and functional recovery after hip fracture

Objective: To evaluate the association between serum levels of 25-hydroxyvitamin D (25[OH]D-3) and functional recovery after hip fracture. Design: Cross-sectional study. Setting: Rehabilitation hospital in Italy. Participants: A total of 350 white hip-fracture patients consecutively admitted to a rehabilitation hospital. Thirty-five patients were excluded because their hip fracture was caused by major trauma or cancer affecting the bone or they could not complete rehabilitation. Interventions: Not applicable. Main Outcome Measures: Patients underwent 25(OH)D-3 assessment at a mean standard deviation of 21.3+/-8.1 days after the hip fracture. Functional recovery was evaluated by using Barthel Index scores. Results: Low levels of 25(OH)D-3 were found (median, 6.9ng/mL). By using the Spearman rank correlation test, a significant positive correlation was observed between serum 25(OH)D-3 and Barthel Index score assessed on admission (rho=.218, P<.001) and discharge (rho=.198, P<.001), but not with the change in Barthel Index score attributable to rehabilitation. Linear multiple regression showed that the association between 25(OH)D-3 and Barthel Index score was independent of 11 confounding variables: age, sex, hip-fracture type, pressure ulcers, cognitive impairment, neurologic impairment, infections, time between fracture occurrence and 25(OH)D-3 evaluation, comorbidity, surgical procedure type, and previous hip fractures. Conclusions: In the study population, serum 25(OH)D-3 was an independent predictor of functional recovery assessed by Barthel Index score after hip fracture but not of the change in the functional score resulting from rehabilitation.