Effect of 800 IU Versus 2000 IU Vitamin D3 With or Without a Simple Home Exercise Program on Functional Recovery After Hip Fracture: A Randomized Controlled Trial.

OBJECTIVES: To evaluate 2 simple strategies, vitamin D3 and a home exercise program, in functional recovery during the first year after hip fracture. DESIGN: Secondary analysis of a factorial clinical trial. Patients were randomly allocated to 800 IU (standard of care) or 2000 IU vitamin D3 and a daily instruction of a simple home exercise program (SHEP) or standard physiotherapy alone during acute care. SETTING AND PARTICIPANTS: Acute hip fracture patients aged ≥65 years, after hip fracture surgery, admitted to a large hospital in Zurich, Switzerland. MEASURES: Three objective measures of lower extremity function were assessed at baseline and 6 and 12 months, with the Timed Up and Go test (TUG) as the primary endpoint, and knee flexor and extensor strength, and a self-reported physical function score (PF-10) as secondary endpoints. Linear mixed model regression analyses were based on intention to treat, adjusting for baseline function, time, age, sex, and baseline 25-hydroxyvitamin D level. RESULTS: We enrolled 173 patients (79.2% women; mean age 84 years; 77.5% living at home). A significant interaction was found between vitamin D3 dose and SHEP for TUG (P = .045). Thus, findings compared the standard of care reference arm with 800 IU vitamin D3 without SHEP to 3 interventions arms (800 IU vitamin D3+SHEP; 2000 IU vitamin D3 without SHEP; 2000 IU vitamin D3+SHEP). For TUG, over 12 months the 800 IU vitamin D3+SHEP group performed significantly better than the standard-of-care group (13.8 vs 19.5 seconds; P = .01). Findings for knee flexor strength were in line with TUG results and approached significance (P = .07), whereas knee extensor strength and PF-10 did not differ by treatments. CONCLUSIONS/IMPLICATIONS: For functional recovery after hip fracture, combining home exercise with 800 IU vitamin D3 is superior to no home exercise or 2000 IU vitamin D3. None of the interventions improved subjective physical functioning.