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

Abstract Objectives To evaluate 2 simple strategies, vitamin D 3 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 D 3 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 D 3 dose and SHEP for TUG ( P  = .045). Thus, findings compared the standard of care reference arm with 800 IU vitamin D 3 without SHEP to 3 interventions arms (800 IU vitamin D 3 +SHEP; 2000 IU vitamin D 3 without SHEP; 2000 IU vitamin D 3 +SHEP). For TUG, over 12 months the 800 IU vitamin D 3 +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 D 3 is superior to no home exercise or 2000 IU vitamin D 3 . None of the interventions improved subjective physical functioning.