Impact of vitamin D status on statin-induced myopathy

INTRODUCTION: There is a multitude of evidence supporting the benefit of statin use in cardiovascular disease; however, statin-induced myopathy is a major reason for statin discontinuation and non-adherence. Vitamin D deficiency has been independently associated with muscle weakness and severe myopathy, and may be a confounder for statin-induced myopathies. Since there is no consensus on a treatment course of action for statin-induced myopathy, investigation into potential confounders to elucidate the dynamics of statin-induced myopathy is warranted. METHODS: A retrospective chart review was conducted on 105 patients in a cardiometabolic clinic with a vitamin D drawn from December 2006 to April 2008. Patients exposed to statins were divided into two groups: (1) patients with low vitamin D (<32 ng/mL) [n = 52] and (2) patients with a sufficient vitamin D level (⩾32 ng/mL) [n = 32]. Data were compared via t-tests or Fisher’s Exact, as appropriate. RESULTS: There were 41 statin-specific myopathies amongst the 24 statin-intolerant patients. Low vitamin D was significantly associated with statin-induced myopathy (p = 0.048). Following prescription vitamin D supplementation, statin tolerance rates were significantly higher in patients with a baseline vitamin D ⩽20 ng/mL than those with a baseline vitamin D >20 ng/mL (90% vs 33%; p = 0.036). CONCLUSION: Vitamin D status may be considered a modifiable risk factor for muscle-related adverse effects of statins, and supplementation of vitamin D (particularly when ⩽20 ng/mL) may improve statin tolerance.