Objectives: To characterize the risk factors, rate of occurrence, onset, nature and impact of mild to moderate muscular symptoms with high-dosage HMG-CoA reductase inhibitor (statin) therapy in general practice.

Methods: The Prédiction du Risque Musculaire en Observationnel (Prediction of Muscular Risk in Observational conditions, PRIMO) survey was an observational study of muscular symptoms in an unselected population of 7924 hyperlipidemic patients receiving high-dosage statin therapy in a usual care, outpatient setting in France. Information on patient demographics, treatment history and muscular symptoms was obtained by question-naires.

Results: Multivariate analysis revealed the strongest predictors for muscular symptoms to be a personal history of muscle pain during lipid-lowering therapy (odds ratio, OR, 10.12, 95% CI 8.23–12.45; P < 0.0001), unexplained cramps (OR 4.14; 95% CI 3.46–4.95; P < 0.0001) and a history of creatine kinase (CK) elevation (OR 2.04; 95% CI 1.55–2.68; P < 0.0001). Overall, muscular symptoms were reported by 832 patients (10.5%), with a median time of onset of 1 month following initiation of statin therapy. Muscular pain prevented even moderate exertion during everyday activities in 315 patients (38%), while 31 (4%) were confined to bed or unable to work. Fluvastatin XL was associated with the lowest rate of muscular symptoms (5.1%) among individual statins.

Conclusion: PRIMO demonstrated that mild to moderate muscular symptoms with high-dosage statin therapy may be more common and exert a greater impact on everyday lives than previously thought. Knowledge of the risk factors for muscular symptoms will allow identification and improved management of high-risk patients. The risk of muscular symptoms with fluvastatin XL treatment may be lower than with high dosages of other statins.