Suboptimal statin adherence and discontinuation in primary and secondary prevention populations.
OBJECTIVE
To compare statin nonadherence and discontinuation rates of primary and secondary prevention populations and to identify factors that may affect those suboptimal medication-taking behaviors.


METHODS
Retrospective cohort utilizing pharmacy claims and administrative databases.


METHODS
A midwestern U.S. university-affiliated hospital and managed care organization (MCO).


METHODS
Non-Medicaid MCO enrollees, 18 years old and older, who filled 2 or more statin prescriptions from January 1998 to November 2001; 2258 secondary and 2544 primary prevention patients were identified.


METHODS
Nonadherence was assessed by the percent of days without medication (gap) over days of active statin use, a measurement known as cumulative multiple refill-interval gap (CMG). Discontinuation was identified by cessation of statin refills prior to the end of available pharmacy claims data.


RESULTS
On average, the primary and secondary groups went without medication 20.4% and 21.5% of the time, respectively (P=.149). Primary prevention patients were more likely to discontinue statin therapy relative to the secondary prevention cohort (relative risk [RR], 1.24; 95% confidence interval [CI], 1.08 to 1.43). Several factors influenced nonadherence and discontinuation. Fifty percent of patients whose average monthly statin copayment was < US dollars 10 discontinued by the end of follow-up (3.9 years), whereas 50% of those who paid >US dollars 10 but <or=US dollars 20 and >US dollars 20 discontinued by 2.2 and 1.0 years, respectively (RR, 1.39 and 4.30 relative to <US dollars 10 copay, respectively).


CONCLUSIONS
Statin nonadherence and discontinuation was suboptimal and similar across prevention categories. Incremental efforts, including those that decrease out-of-pocket pharmaceutical expenditures, should focus on improving adherence in high-risk populations most likely to benefit from statin use.
Ellis
Jeffrey J
JJ
Department of Pharmacy Services, University of Michigan Hospitals and Health Centers, Ann Arbor, Michigan, USA. ellisj2@ccf.org
Erickson
Steven R
SR
Stevenson
James G
JG
Bernstein
Steven J
SJ
Stiles
Renee A
RA
Fendrick
A Mark
AM
D015331:Cohort Studies; D003327:Coronary Disease / Q000188:drug therapy* / Q000517:prevention & control*; D003362:Cost-Benefit Analysis; D019992:Databases as Topic; D003695:Delivery of Health Care; D005260:Female; D005382:Financing, Personal; D006785:Hospitals, University; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000191:economics / Q000627:therapeutic use*; D008297:Male; D008329:Managed Care Programs; D008875:Middle Aged; D016017:Odds Ratio; D011322:Primary Prevention; D012189:Retrospective Studies; D012306:Risk; D016019:Survival Analysis; D016312:Treatment Refusal / Q000706:statistics & numerical data; D014481:United States
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors