Parabolas of medication use and discontinuation after myocardial infarction--are we closing the treatment gap?

PURPOSE: Little is known on the use of evidence-based medications in patients with acute myocardial infarction (AMI) across all ages. We undertook this study to describe the patterns of prescription and discontinuation of anti-platelet agents, beta-blockers, angiotensin converting enzyme (ACE) inhibitors and/or angiotensin receptor blockers (ARBs) and statins in all patients post-AMI.

METHODS: Using population-based administrative databases, patients with an AMI between 1999 and 2004 (21 494 men and 13 241 women) were identified. Rates of prescriptions after discharge and time to discontinuation of the study drugs were computed for various age groups.

RESULTS: The proportion of patients prescribed a study drug increased throughout the study period. In 2003-2004, 90% of patients were prescribed an anti-platelet agent, 77% a beta-blocker, 72% a statin and 70% an ACE inhibitor and/or an ARB within 30 days of discharge from their AMI. However, the rates of discontinuation increased significantly during follow-up and, in men, reached 27% by 2 years and 42% by 5 years for beta-blockers. The rates of discontinuation of all four study drugs had a parabolic shape with the youngest and oldest patients having the highest rates.

CONCLUSIONS: The use of evidence-based drugs for patients after AMI is increasing. However, efforts aimed at closing the treatment gap may be mitigated by high rates of discontinuation, especially in patients at the extremes of the age spectrum.