Abstract P391: Temporal Trends in Medical Therapies for Hospitalized ST- and Non-ST Elevation Myocardial Infarction: The Atherosclerosis Risk in Communities (ARIC) Study Community Surveillance

Abstract

Background: Reports from large studies using administrative datasets and event registries have characterized recent temporal trends and treatment patterns for AMI. However, few are population based and fewer have examined differences in patterns of treatment for patients presenting with ST elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction (NSTEMI). We examined 21-year trends in the use of 10 medical therapies and procedures by STEMI and NSTEMI classification in the ARIC Community Surveillance Study. Methods: We analyzed data from an estimated 30,986 definite or probable MIs between 1987 and 2008 among residents 35-74 years of age in the four geographically defined US communities of the ARIC Study. Data on medical therapies was obtained through detailed abstraction of the medical records. Classification of STEMI and NSTEMI was based on independent Minnesota coding of electrocardiograms. We used weighted Poisson regression to estimate annual proportions of patients receiving each medication or procedure and age-standardized these estimates to the 2000 U.S. Census population. We then used weighted multivariable Poisson regression controlling for sex, race/center classification, age, and PREDICT mortality risk score to estimate average annual percent changes in medical therapy use over the study period. Results: From 1987 – 2008, 6106 (19.7%) hospitalized events were classified as STEMI, and 20302 (65.5%) were classified as NSTEMI. Among STEMI patients, increases (%; 95% CI) were noted in the use of ACE inhibitors (6.4; 5.7, 7.2), non-aspirin anti-platelets (5.0; 4.0, 6.0), lipid-lowering medications (4.5; 3.1, 5.8), beta blockers (2.7; 2.4, 3.0), aspirin (1.2; 1.0, 1.3), and heparin (0.8; 0.4, 1.3). Among NSTEMI patients, the use of ACE inhibitors (5.5; 5.0, 6.1), non-aspirin anti-platelets (3.7; 2.7, 4.7), lipid-lowering medications (3.0; 1.9, 4.1), beta blockers (4.2; 3.9, 4.4), aspirin (1.9, 1.6; 2.1), and heparin (1.7; 1.3, 2.1) increased. Calcium channel blocker use decreased for both STEMI (−8.8%;−9.6,−8.0) and NSTEMI (−5.6; −6.1,−5.1) patients over the study period. Among STEMI patients, we observed decreases in the use of thrombolytics (−7.2; −7.9, −6.6) and CABG (−2.4%; −3.6, −1.2). We noted similar decreases in the use of thrombolytics (−9.8; −10.7, −8.8) and CABG (−2.5; −3.3, −1.6) among NSTEMI patients. PCI use increased for both STEMI (6.4; 5.8, 7.0) and NSTEMI (5.1; 4.5, 5.7) patients. Increases in the use of stents were documented for both STEMI (4.5; 2.7, 6.2) and NSTEMI patients (1.3; −0.5, 3.2). Conclusion: We found trends of increasing use of evidence-based medicine for both STEMI and NSTEMI patients over the past 21 years. Future research should examine the broader public health impact of increasing adherence to clinical therapy guidelines.