Clinical and Economic Outcomes of Conversion of Simvastatin to Lovastatin in a Group-Model Health Maintenance Organization

OBJECTIVES: To (a) determine if converting patients on simvastatin to lovastatin affects whether they meet their low-density lipoprotein cholesterol (LDL-C) goals as defined by the National Cholesterol Education Program Adult Treatment Panel III (ATP III) clinical practice guidelines and (b) assess the change in health care expenditures associated with such a conversion. METHODS: Primary and secondary prevention patients receiving simvastatin 10 mg to 40 mg daily between September 1, 2001, and February 28, 2002, were offered lovastatin at a therapeutically equivalent dose. Fasting lipid profiles and alanine aminotransferase (ALT) levels were measured and recorded at least 6 weeks after starting lovastatin. A clinical pharmacy staff member, in collaboration with the subjects primary care provider, subsequently adjusted lipid-lowering therapy as needed to attain target LDL-C goals, as determined by the ATP III clinical practice guidelines. RESULTS: Of 5,286 patients converted to lovastatin and for whom follow-up laboratory tests were drawn, 5,046 (95.5%) were converted successfully, and 240 (4.5%) had to be converted back to simvastatin due to intolerance (N=164, 3.1%) or failure to achieve LDL-C goal (N=76, 1.4%). The proportion of patients with LDL-C at or less than their target goal increased from 75.9% before the intervention to 79.1% after conversion to lovastatin (P less than 0.001). ALT levels did not change significantly. The mean ALT value, a proxy measure of safety before and after conversion for all patients, was 26.9 IU/L and 26.4 IU/L, respectively (P=0.134). For the 2,235 patients converted from lovastatin 80 mg to simvastatin 40 mg, the mean pre-ALT and post-ALT values were 26.9 IU/L and 26.5 IU/L (P=0.498). The annualized cost savings due to the conversions, expressed across the entire membership of this health maintenance organization (HMO), was $4.14 per member per year (PMPY), with no change in ALT levels. Patient savings in reduced copayments in the conversion from brand simvastatin to generic lovastatin were an average of $145.29 (62%) per patient (95% confidence interval, $143-$149, P less than 0.001). CONCLUSIONS: A clinical pharmacy-directed program designed to convert patients from simvastatin to lovastatin resulted in substantial expenditure reductions for this HMO and 62% copayment savings for members, without compromise in clinical outcomes as measured by lipid control (effectiveness) and ALT levels (safety). The proportion of patients at or less than their LDL-C goal increased coincident with the conversion from simvastatin to lovastatin.