Therapy modifications and low-density lipoprotein cholesterol goal attainment rates associated with the initiation of generic simvastatin

Abstract

Objective:The availability of generic simvastatin has changed the relative cost structure within the statin marketplace and has been associated with third-party payer changes to formularies and statin utilization policies. The current study examines simvastatin therapy modification patterns and associated low-density lipoprotein cholesterol (LDL-C) goal attainment rates.Methods:This retrospective, observational study utilized administrative claims linked to laboratory result data from a national health plan. Patients newly initiated on generic simvastatin from January 2007 to March 2008 were identified. National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) risk categories and goal LDL-C targets were assigned. Simvastatin dose titrations and switches to other statins were described, as were changes in LDL-C values and NCEP ATP III goal attainment rates both before and after therapy modifications.Results:Of the 1654 patients newly initiated on simvastatin, 84% had no simvastatin therapy modification in the >1-year follow-up period. For patients with no therapy modification, 54.4% did not achieve their LDL-C NCEP ATP III goal at their first lipid panel and goal attainment was strongly associated with the level of cardiovascular risk (goal attainment rate = 75.1%, 51.7%, and 28.6% for low-, moderate- and high-risk categories, respectively). Of patients not achieving NCEP ATP III LDL-C goals (n = 885), 85.4% had no therapy modification. Goal was achieved after therapy modification in 36% (dose titration) and 42% (switchers); high-risk patients goal attainment rates were 23% and 38%, respectively.Limitations:Limitations of the study include the observational design, use of an administrative claims database to assess cardiovascular risk, relatively short follow-up time (slightly more than 1 year) and the lack of assessment of adherence to therapy.Conclusions:This study found that the majority of patients initiated on generic simvastatin stayed on their initial starting dose regardless of NCEP ATP III goal attainment status. The findings of low rates of therapy modification irrespective of baseline CV risk and associated low rates of goal attainment, especially in high risk patients treated with simvastatin, indicate an opportunity to encourage clinical decision making based on the needs of the individual patient.