Utilization and discontinuation of secondary prevention pharmacotherapy after myocardial infarction: a nationwide...

To analyse utilization and discontinuation of secondary preventive medications after acute myocardial infarction (MI).

In separate analyses for each drug [statins, beta-blockers, aspirin, and renin-angiotensin-aldosterone system (RAAS) inhibitors], patients with a first-time MI (2006-2021) registered in the nationwide Swedish MI register SWEDEHEART, surviving >30 days, and discharged with a new prescription of the drug were included. Based on filled prescriptions, treatment initiation, discontinuation (defined as ≥90-day period of non-treatment after the end of previous prescriptions), reinitiation (restarting treatment after discontinuation), and the proportion of patients with ongoing treatment at various time points after the MI were assessed. The analyses included 159 155 patients: 122 288 patients discharged with a statin, 79 968 with a RAAS inhibitor, 105 095 with a beta-blocker, and 127 463 with aspirin: 95%-97% of the patients filled their first prescription for the drug. Treatment discontinuation ranged from 12% to 14% at 1 year, 27%-37% at 5 years, and 36%-51% at 12 years across drugs. Among those who discontinued treatment, the proportion who reinitiated treatment was 28%-46% at 1 year, 42%-62% at 5 years, and 47%-67% at 12 years after discontinuation across drugs. The proportion of patients who were alive with ongoing treatment (regardless of previous discontinuation/reinitiation episodes) was 91%-92% at 1 year, 79%-82% at 5 years, and 74%-79% at 12 years after the index MI.

Discontinuation of secondary preventive medications was common, but so was reinitiation. Thus, the proportion of patients with ongoing treatment was 91%-92% at 1 year and 74%-79% at 12 years after the MI. This study, which did not assess reasons for drug discontinuation, indicates that long-term utilization of secondary preventive medication after MI may not be as low as previously thought.