Association of Vitamin D and Incident Statin Induced Myalgia—A Retrospective Cohort Study

BACKGROUND AND OBJECTIVES Evidence is conflicting with regards to the role of vitamin D in statin induced myalgia (SIM). Studies so far have assessed cross-sectional association and were limited by study sample selected predominantly from cardiology clinics. In this retrospective cohort study we assessed the association between vitamin D and SIM and attempted to establish a serum vitamin D cutoff to identify patients at risk for developing SIM. METHODS Medical charts of 5526 consecutive patients from a primary care practice in Scranton, Pennsylvania from 2005-2012 were reviewed. Vitamin D level (25-hydroxy cholecalciferol) at statin initiation was considered "Exposure level". Vitamin D levels were categorized into quartiles (≤ 10, 11-20, 21-30, >30 ng/ml). SIM was identified by patient report. RESULTS 1160 out of 5526 patients were treated with statins. The mean age was 55.9 years. 276 (24%) developed SIM. Unadjusted 7-yr cumulative incidences of SIM for quartiles 1-4 of vitamin D were 32.3, 21.5, 18.3 and 14.6% respectively. The lowest quartile of vitamin D was independently associated with 1.21 times the hazard of the fourth quartile for developing SIM (95% CI: 1.09, 1.33; P-trend  = 0.001). Vitamin D cut-off ≤15 ng/ml, showed a positive predictive value, negative predictive value, likelihood ratio (LR) + and LR- of 81, 90, 5.1 and 0.1, respectively for predicting SIM. CONCLUSIONS Low vitamin D level at statin initiation is associated with SIM, levels ≤15 ng/ml have a high predictive accuracy for SIM. Randomized controlled trials are needed to validate our results.