Statin associated muscle symptoms and therapy adherence

Abstract

Statin associated muscle symptoms (SAMS) may lead to therapy non-adherence and discontinuation. Clinical presentation of SAMS is highly heterogeneous and there are no standardised definitions of SAMS terminologies. The aims were to: 1) Assess adherence and patient experience with statin therapy in a patient cohort undergoing cardiac procedures, and 2) Propose harmonised definitions of SAMS terminologies. The methodology consisted of: 1) Development and validation of a data collection sheet and questionnaire, prospective recruitment of patients on statin therapy who underwent coronary angiography (n=125) or percutaneous coronary intervention (PCI) (n=125) by convenience sampling, and completion of data collection tools using hospital records and patient interview; 2) Compilation of SAMS terminologies definitions from literature, identification of definitions used by cardiologists in practice using a self-administered online questionnaire, followed by proposal of harmonised definitions and validation by an interprofessional focus group. Descriptive statistics were performed. From the 250 patients assessed (75% male, 39% between 65 and 74 years), 65% were prescribed atorvastatin. There was no significant difference in patient responses between coronary angiography and PCI (p>0.05). Forty-one percent of patients ‘sometimes’ or ‘frequently’ skip a dose, mostly attributed to forgetfulness (47%). Sixteen percent considered stopping the statin without consulting a healthcare professional. SAMS were reported by 28% (n=70) of patients, mostly myalgia (n=54), which made them feel tired requiring rest (n=61). Most patients experiencing SAMS (n=56) informed a physician, and statin was changed in 20 patients. The statin mostly implicated with SAMS was simvastatin (50%). Definitions for myalgia (n=8), myopathy (n=8) and rhabdomyolysis (n=7) were identified from literature. Four definitions for myalgia and myopathy, and 6 definitions for rhabdomyolysis were identified by nine cardiologists as used in practice. A harmonised definition for each terminology was compiled. Following consensus in the focus group, the harmonised definitions were disseminated to cardiologists. Adherence to statin therapy in the cohort studied is not optimal and patients reported SAMS which impacted their quality of life. Data indicating duration of statin therapy was not available and may have inference on adherence and side-effects reporting. Harmonised definitions of SAMS terminologies may support cardiologists in diagnosis and management of SAMS to facilitate management of statin therapy.