Understanding practice patterns and low-density lipoprotein cholesterol goal attainment implications of switching patients from simvastatin in a health plan setting

Abstract

Objective: To understand the practice patterns and National Cholesterol Education Panel (NCEP) Adult Treatment Panel (ATP) III low-density lipoprotein cholesterol (LDL-C) goal attainment rates after switching patients from simvastatin (SMV) to other statins or the combination of SMV and ezetimibe (EZE).

Methods: This retrospective study linked claims and laboratory data from a national health plan. Patients were included if they were taking SMV and were switched to other statins or a fixed-dose combination of SMV and EZE between July 1, 2005, and June 30, 2006. Patients taking dual SMV/EZE before switch were excluded from the study. The NCEP ATP III risk status of patients at switch was assessed based on medical claims, pharmacy claims, and laboratory values in the 12-month preswitch period. Lipid data (available on a patient subset) were used to estimate patients' goal attainment status at and after switch.

Results: Of 134 168 patients taking SMV, 11 929 (8.9%) switched to other statins or SMV/EZE. The mean age of switching patients was 54 years (standard deviation, 9 years), 61% were men, 50% were high risk, and 30% were moderate risk. The mean time to switch among new starters of SMV (n = 3379) was 77 days. Forty percent (n = 4772) of the total switches occurred among those taking the lower doses (5, 10, and 20 mg) of SMV. Most patients switched from SMV to SMV/EZE (60.5%), followed by atorvastatin (17.3%), rosuvastatin (10.1%), lovastatin (8.6%), pravastatin (2.9%), and fluvastatin (0.7%). Similarly, most patients switching from higher doses of SMV switched to SMV/EZE (52.5%), followed by atorrestatin (21.1%) and rosuvastatin (10.1%). Overall, 55.6% (758 of 1362) of patients were at ATP III goal at the time of switch from SMV (across all doses; n = 758), and 56.1% (292 of 521) of those taking lower doses were at goal at time of switch. A majority (69.9%) of patients who were at goal and switched from SMV (across all doses) were switched to SMV/EZE, and 61.6% of those at lower doses of SMV switched to the combination drug. Of patients who were not at goal at switch (n = 604), 73.3% attained ATP III LDL-C goal after switch. The mean percent LDL-C reduction that was needed to attain LDL-C goal at switch from SMV (n = 604) was 18.1%.

Conclusions: There is an opportunity to further increase LDL-C goal attainment rates among patients switched from SMV. The clinical, prescription benefit design, and economic implications of the finding that a majority of patients are at goal when switched from SMV and a majority of patients are being switched from SMV to SMV/EZE need to be further examined.