Adherence to beta-blocker therapy under drug cost-sharing in patients with and without acute myocardial infarction.
OBJECTIVE
To evaluate the effects of patient copayment and coinsurance policies on adherence to therapy with beta-adrenergic blocking agents (beta-blockers) and on the rate of initiation of beta-blocker therapy after acute myocardial infarction (MI) in a population-based natural experiment.


METHODS
Three sequential cohorts included British Columbia residents age 66 years and older who initiated beta-blocker therapy during time intervals with full drug coverage (2001), a $10 or $25 copayment (2002), and 25% coinsurance (2003-2004). We used linked data on all prescription drug dispensings, physician services, and hospitalizations. Follow-up of each cohort was 9 months after the policy changes.


METHODS
We measured the proportion of subjects in each cohort who were adherent to beta-blocker therapy over time, with adherence defined as having >80% of days covered. We also measured the proportion of patients initiating beta-blocker therapy after acute MI. Policy effects were evaluated using multivariable regression.


RESULTS
Adherence to beta-blocker therapy was marginally reduced as a consequence of the copayment policy (-1.3 percentage points, 95% confidence interval [CI] = -2.5 , -0.04) or the coinsurance policy (-0.8 percentage points, 95% CI = -2.0, 0.3). The proportion of patients initiating beta-blockers after hospitalization for acute MI remained steady at about 61% during the study period, similar to that observed in a control population of elderly Pennsylvania residents with full drug coverage.


CONCLUSIONS
Fixed patient copayment and coinsurance policies had little negative effect on adherence to relatively inexpensive beta-blocker therapy, or initiation of beta-blockers after acute MI.
Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, 1620 Tremont St (Ste 3030), Boston, MA 02120, USA. schneeweiss@post.harvard.edu
Sebastian
S
Schneeweiss
Amanda R
AR
Patrick
Malcolm
M
Maclure
Colin R
CR
Dormuth
Robert J
RJ
Glynn
D000208:Acute Disease; D000319:Adrenergic beta-Antagonists / Q000191:economics* / Q000627:therapeutic use; D000368:Aged; D000369:Aged, 80 and over; D001955:British Columbia; D016022:Case-Control Studies; D015331:Cohort Studies; D015897:Comorbidity; D017047:Cost Sharing; D003669:Deductibles and Coinsurance; D048909:Diabetes Complications; D005260:Female; D006291:Health Policy / Q000639:trends; D006801:Humans; D008297:Male; D008498:Medical Record Linkage; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000191:economics; D010349:Patient Compliance / Q000706:statistics & numerical data*; D011306:Prescription Fees; D014652:Vascular Diseases
D000319:Adrenergic beta-Antagonists