Is there clinical benefit to routine enzyme testing of patients on statins?

Objective: Statin-treated patients undergo frequent laboratory tests. This study evaluated the clinical impact of abnormal liver or muscle enzyme results. Research design and methods: This clinical process evaluation study took place in six primary care clinics in Israel. Four hundred and eight patients (average age 63.8 ± 10.9 years) undergoing statin treatment, with at least one enzyme level > 10% normal, were categorized by symptomatology possibly related to statins. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and creatine phosphokinase were measured. Management and etiology of the elevation were assessed. Main outcome measures: Changes in statin regimen. Results: Thirty-six (8.8%) patients were symptomatic at the index encounter. One enzyme was elevated in 74.8%. Patients experiencing side effects had more repeat tests (36.1 vs 17.7%, p < 0.001). Musculoskeletal symptoms resulted in a change in treatment more than digestive symptoms did (73.3 vs 16.7%, p < 0.001). Of 40 (9.8%) patients who had additional evaluation, two symptomatic patients had treatment changes. Conclusions: There is little practical value in routine follow-up enzyme tests for patients on statins. Our findings strengthen reports that recommend muscle and liver enzyme tests for symptomatic patients only.