Clinical factors, psychological factors and beliefs about statin use in patients with coronary heart disease and self-perceived muscle side-effects

Abstract

Abstract Background Statin associated muscle symptoms (SAMS) are commonly reported and constitute the principal reason for statin non-adherence and/or discontinuation. Understanding the determinants of SAMS may enhance the clinical management and form the basis of interventions. The association between psychological distress and the beliefs about statin treatment and SAMS have previously not been investigated under randomized, controlled conditions. Purpose To compare clinical and psychological factors among coronary patients with confirmed SAMS and non-SAMS. Methods This pre-planned exploratory study included 71 consecutively recruited patients with self-perceived SAMS enrolled in the MUscle Side-Effect of atorvastatin in coronary patients (MUSE) randomized double-blinded crossover trial. Muscle symptom (pain, weakness, tenderness, stiffness and/or cramps) intensity was registered weekly in a patient diary using a 0 (no symptoms) to 10 (worst imaginable) cm visual-analogue scale (VAS). Confirmed SAMS was predefined as a 25% higher individual mean VAS-scores during 7-weeks treatment with atorvastatin 40 mg/day versus 7-weeks treatment with placebo, and ≥1cm absolute difference. Clinical factors (10 variables), psychological factors (5 variables) and beliefs about medicine (3 variables) were obtained from a questionnaire and a clinical examination at study start. Results Mean age was 63 (SD 9.5) years, 32% were women, and each participant had tried average 1.3 (SD 0.6, range 1 to 3) statins prior to study start. In all, 28% (n=20) had confirmed SAMS and 72% (n=51) had non-SAMS. There were no differences in mean VAS score at study start between the groups (mean VAS score 4.5 vs. 4.7, p=0.20). More patients with confirmed SAMS than non-SAMS (25% vs. 6%, p<0.001) did not use statin treatment at study start, and mean LDL-cholesterol level was borderline higher (2.8 vs. 2.3 mmol/L, p=0.06). Patients with confirmed SAMS had a weaker belief in their statin use compared to patients with non-SAMS (3.1 vs. 3.6, p<0.001) using a 5-category scale from 1 (weak belief) to 5 (strongest belief). There were no differences in the sociodemographic, clinical (pre-existing muscle skeletal disorders, somatic comorbidity, cardiovascular risk factors) or psychological (symptoms of anxiety or depression, type D personality, worry, insomnia) factors explored between patients with confirmed SAMS or with non-SAMS. There were no associations between these factors and increasing VAS scores in continuous analyses among patients with confirmed SAMS and non-SAMS. Conclusions Patients with statin dependent muscle side-effects reported a weaker belief on the necessity to take statins than patients with muscle complaints not caused by the statin. Otherwise, we found no differences in clinical or psychological factors between these populations. The results indicate that these factors do not distinguish patients with and without associated muscle symptoms in clinical practice. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Vestfold Hospital Trust, research grant