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Effect of evidence‐based drug therapy on long‐term outcomes in patients discharged after myocardial infarction: a nested case–control study in Italy
Author(s) -
Kirchmayer Ursula,
Di Martino Mirko,
Agabiti Nera,
Bauleo Lisa,
Fusco Danilo,
Belleudi Valeria,
Arcà Massimo,
Pinnarelli Luigi,
Perucci Carlo Alberto,
Davoli Marina
Publication year - 2013
Publication title -
pharmacoepidemiology and drug safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.023
H-Index - 96
eISSN - 1099-1557
pISSN - 1053-8569
DOI - 10.1002/pds.3430
Subject(s) - medicine , myocardial infarction , nested case control study , pharmacoepidemiology , observational study , logistic regression , drug , cohort study , revascularization , population , combination therapy , cohort , pharmacology , environmental health , medical prescription
Purpose There are some methodological concerns regarding results from observational studies about the effectiveness of evidence‐based (EB) drug therapy in secondary prevention after myocardial infarction. The present study used a nested case–control approach to address these major methodological limitations. Methods A cohort of 6880 patients discharged from hospital after acute myocardial infarction (AMI) in 2006–2007 was enrolled and followed‐up throughout 2009. Exposure was defined as adherence to each drug in terms of the proportion of days covered (cutoff ≥ 75%). Composite treatment groups, that is, groups with no EB therapy or therapy with one, two, three, or four EB drugs), were analyzed. Outcomes were overall mortality and reinfarction. Nested case–control studies were performed for both outcomes, matching four controls to every case (841 deaths, 778 reinfarctions) by gender, age, and individual follow‐up. The association between exposure to EB drug therapy and outcomes was analyzed using conditional logistic regression, adjusting for revascularization procedures, comorbidities, duration of index admission, and use of the study drugs prior to admission. Results Mortality and reinfarction risk decreased with the use of an increasing number of EB drugs. Combinations of two or more EB drugs were associated with a significant protective effect ( p < 0.001) versus no EB drugs (mortality: 4 EB drugs: OR adj = 0.35; 95%CI: 0.21–0.59; reinfarction: 4 EB drugs: OR adj = 0.23; 95%CI: 0.15–0.37). Conclusions These findings of the beneficial effects of EB polytherapy on mortality and morbidity in a population‐based setting using a nested case–control approach strengthen existing evidence from observational studies. Copyright © 2013 John Wiley & Sons, Ltd.