Statin-induced myopathy in a usual care setting—a prospective observational study of gender differences

Abstract

PURPOSE: The study aims to identify the occurrence and remission of statin-induced myopathy including patient perception and symptom characteristics with a gender perspective. METHODS: The study was designed as a prospective, non-interventional investigation in 192 outpatients receiving statin treatment in usual care with 12 months follow-up. Main outcome measure was myopathy related to statin treatment and classified as probable using WHO criteria for adverse drug reaction (ADR) assessment. RESULTS: Fourteen percent developed myopathy, risk ratio for women 1.52 [95 % CI 1.37; 1.66] as compared to men. The majority graded their pain as "severe." CK values were within normal range. Eighty percent of the women compared to 43 % of the men reported that the muscular symptoms affected their daily life activities to a moderate or severe extent. For those who stopped treatment, mypopathy was the reason for 70 % of the women and 25 % of the men. There was a difference in mean dose between men with and without myopathy, but not in women. Among the patients with myopathy, 76 % reported other ADRs as compared to 21 % of the patients without myopathy (p = 0.002). Twenty-nine percent of the women and 18 % of the men reported other ADRs. CONCLUSION: Women reported a higher frequency of myopathy and other ADRs as well as a larger impact on daily life activities. In men, but not in women, the risk of myopathy was dose-dependent. Patients with myopathy were more susceptible to other statin-induced ADRs which raises the question about common underlying mechanisms.