Statin adverse effects: patients' experiences and laboratory monitoring of muscle and liver injuries.

Background: Although statins have great benefit on the prevention of cardiovascular diseases with limited adverse effects (AEs), little is known about patients' contribution of AE reports in clinical practice.

Objectives: To explore patients' experiences of statin AEs and related laboratory monitoring in clinical practice.

Setting: Outpatient clinics of two University hospitals in northeast Thailand.

Methods: Generic symptom checklist questionnaires for self-reporting AEs were distributed to patients prescribed simvastatin, atorvastatin, or rosuvastatin at outpatient clinics. Clinical information was obtained from medical records. Reported symptoms were assessed for causality considering previously known statin AEs, concomitant diseases and drugs.

Main Outcome Measure: Potential statin AEs reported by patients and monitoring of laboratory parameters related to musculoskeletal and liver disorders.

Results: Of the total 718 valid responses, 76.0 % of patients reported at least one symptom, most of which (69.0 %) were probable/possible statin AEs. Musculoskeletal and liver-related symptoms were reported by 283 (39.4 %) and 134 patients (18.7 %), respectively. Probable/possible AEs were categorized in 56.7 % of their musculoskeletal and gastrointestinal symptoms. Majority of patients had at least one laboratory test on initiation of (64.8 %) and during statin treatment (61.8 %). Patients taking atorvastatin or rosuvastatin, and patients with history of chronic renal diseases were more likely to have creatine kinase (CK) monitored on initiation of and during statin treatment. Additionally, taking drugs which could potentially increase muscle injury (OR 1.929, P < 0.01) and self-reporting of musculoskeletal symptoms (OR 1.805, P < 0.01) were associated with CK monitoring during statin treatment. Reporters of musculoskeletal symptoms also had significantly higher mean CK level than those not reporting any musculoskeletal symptoms (207.35 ± 155.40 vs. 143.95 ± 83.07 U/L, respectively; P = 0.037). Patient reporting of liver AEs was not related to alanine aminotransferase (ALT) level and monitoring, however, prior history of liver disorders was significantly associated with monitoring of ALT on initiation of and during statin treatment (OR 5.745 and OR 23.063, respectively; P < 0.01).

Conclusion: Many patients experienced at least one possible adverse effects on a statin. The findings suggest that laboratory monitoring is relatively selective in relation to risks and patient-reported adverse symptoms.