Clinical and economic outcomes of conversion of simvastatin to lovastatin in a group-model health maintenance organization.

OBJECTIVE 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 subject's 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 <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 US dollars 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 US dollars (62%) per patient (95% confidence interval, 143-149 US dollars, P <0.001). CONCLUSION 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.