Prescription prevalence and continuing medication use for secondary prevention after myocardial infarction: the reality of care revealed by claims data analysis.

BACKGROUND: Current guidelines recommend using aspirin, clopidogrel, beta-blockers, statins, and angiotensin converting enzyme (ACE) inhibitors after acute myocardial infarction (AMI). Although there is evidence that patients often stop taking these medications prematurely, long-term data reflecting the actual reality of care are lacking. We studied prescription prevalence and treatment persistence of secondary prevention in patients who had an AMI by analyzing relevant claims data from a German sickness fund, the Techniker Krankenkasse (these data are not necessarily representative of the entire German population).
METHODS: Insurees who were discharged from the hospital between 2001 and 2006 with AMI as their main discharge diagnosis were classified as users or non-users of each of the types of drug listed above on the basis of the prescriptions that they obtained in the first 90 days after they left the hospital. Treatment persistence was statistically assessed with survival analysis. Switches from one drug class to another were not examined.
RESULTS: Of 30,028 AMI patients, 82% were initially prescribed a beta-blocker, 73% a statin, 69% an ACE inhibitor, 66% aspirin (without self-medication), and 61% clopidogrel. Five years after discharge, 10% of the patients for whom aspirin was initially prescribed were still taking it; the corresponding figures for the other drug classes were 17% for statins, 31% for ACE inhibitors, and 36% for beta-blockers. The greatest drop in treatment persistence occurred approximately one year after the AMI.
CONCLUSION: Treatment persistence with recommended medication after AMI is still in need of improvement. Patient education should start as soon as possible after infarction, because the greatest drops in medication use appear to occur within one year after AMI.