The effects of cost-sharing on essential drug prescriptions, utilization of medical care and outcomes after acute myocardial infarction in elderly patients

Abstract

Background: After a change in Quebec's policy on drug coverage in August 1996, elderly patients' copayments for prescription drugs increased. We assessed the impact of this drug policy reform on prescribing patterns for essential cardiac medications, utilization of medical care and related health outcomes after acute myocardial infarction.

Methods: Patients at least 65 years of age who experienced acute myocardial infarction between 1994 and 1998 were identified through the Quebec discharge summary database. Drug claims databases were analyzed to determine rates of prescription of essential cardiac medications for cohorts of patients admitted before and after the policy reform. The impact on readmissions for cardiac-related complications, outpatient visits to physicians and emergency departments, and mortality rate was also assessed.

Results: The proportion of patients who received prescriptions for beta-blockers, angiotensin-converting enzyme inhibitors and lipid-lowering drugs increased over time and, more specifically, did not appear to decline with the change in the drug policy. In addition, the policy reform did not appear to affect persistence of drug therapy (the proportion of time for which patients were covered by prescriptions over the year after discharge). There was no within-class shift from more to less expensive drugs. Use of cardiac procedures increased over time, but this increase was unrelated to the date of the policy reform. Finally, rates of readmission for complications, visits to individual physicians and to emergency departments, and mortality rate were unchanged. The findings did not vary with sex or socioeconomic status.

Interpretation: Prescriptions for essential cardiac medications and care related to acute myocardial infarction in elderly patients did not change with increases in out-of-pocket copayment, regardless of sex or socioeconomic status.

Fig. 1: Discharge prescriptions and persistence of drug therapy (proportion of time during the first year after discharge that a patient was covered by the medication in question), with 95% confidence intervals, for cardiac drugs prescribed for patients with acute myocardial infarction for a 2-month period before and a 1-month period after changes in Quebec's drug coverage policy. The major changes in the drug policy took place on Aug. 1, 1996, and Jan. 1, 1997. ACE = angiotensin-converting enzyme.