被撤回的出版物: An Open-Label Trial Comparing Alendronate and Alphacalcidol in Reducing Falls and Hip Fractures in Disabled Stroke Patients (Retracted article. See vol. 28, 2019)

Although vitamin D supplementation has been suggested to reduce the risk of falling in ambulatory or institutionalized elderly persons, no study has examined whether it reduces the frequency of falling in immobilized stroke patients who have immobilization-induced hypercalcemia reflecting increased bone resorption leading to inhibited renal synthesis of 1, 25-dihydroxyvitamin D (1, 25-[OH]2D). Bisphosphonate is known to reduce immobilization-induced hypercalcemia by inhibiting bone resorption of calcium. This study compared the efficacy of 2 drugs in reducing the risk of falling in patients with long-standing stroke. Eighty-two elderly patients with poststroke hemiparesis were followed for 1 year. The patients were randomly assigned to one of 2 groups; 41 patients received alendronate 35 mg once weekly, and 41 patients received alphacalcidiol 1 mu g daily. The number of falls per person and incidence of hip fracture in the 2 groups were compared. At baseline, all patients had a low serum 1, 25-[OH]2D level. Alphacalcidol therapy enhanced immobilization-induced hypercalcemia by increasing intestinal calcium absorption, leading to a reduction of serum 1, 25-[OH]2D level, while alendronate therapy enhanced 1, 25-[OH]2D production by decreasing hypercalcemia. Alendronate treatment accounted for a 55% reduction in falls (95% confidence interval [Cl] = 25-72%; P = .0021). During the 1-year study period, hip fracture occurred in 1 of 41 subjects in the alphacalcidol group and in no subjects in the alendronate group. Bone mineral density was increased by 3.2% in the alendronate group and decreased by 0.1% in the alphacalcidol group (P < .0001). Alendronate therapy increased serum 1, 25-[OH]2D levels by improving immobilization-induced hypercalcemia, which may lead to decreased falling and subsequent hip fractures.