Vitamin K2 as a potential therapeutic candidate for the prevention of muscle cramps in hemodialysis patients: A prospective multicenter, randomized, controlled, crossover pilot trial.

OBJECTIVES Muscle cramps occur in 33% to 78% of patients with dialysis. The etiology of muscle cramps is poorly understood, and no clear evidence-based prevention or treatment strategies exist. Improved interventions are urgently needed. The aim of this study was to investigate the effect of vitamin K2 in reducing the frequency and severity of muscle cramps in hemodialysis (HD) patients. METHODS This multicenter, randomized, placebo-controlled, crossover clinical trial was conducted from June 2019 to May 2020. Each participant received vitamin K2 (360 µg/d) or placebo for two 4-wk phases, and then crossed to the alternative arm for two 4-wk phases after a 2-wk washout. The primary endpoint was the frequency of muscle cramps during HD. The secondary endpoints were severity and duration of muscle cramps during HD. RESULTS A total of 523 patients with maintenance HD were screened for muscle cramps, including 41 patients with muscle cramps refractory to conventional interventions, were enrolled. Nineteen patients in the vitamin K2-initial group and 20 in the placebo-initial group completed the protocol, and were included in the final analysis. Vitamin K2 reduced the frequency, duration, and severity of muscle cramps in HD patients (all P < 0.05). The frequency, duration, and severity of muscle cramps in HD patients increased again after crossing over to the placebo. There were no serious adverse events. One patient experienced gastrointestinal discomfort when taking vitamin K2. CONCLUSIONS This pilot trial demonstrated that vitamin K2 supplementation could decrease the frequency, duration, and severity of muscle cramps in HD patients.