Abstract 1036: The Effect of Changing Diagnostic Algorithms on Acute Myocardial Infarction Rates
Introduction: Assessment of incidence, prevalence and trends in acute myocardial infarction (AMI) is critical to the understanding of the coronary heart disease epidemic This research requires explicit case definitions. The World Health Organization (WHO) criteria, developed in the 1970’s, form the basis for the diagnosis. However, WHO criteria are ambiguous and variably interpreted. AMI presentation is also changing with milder cases lacking classical ECG findings and increased case finding with more sensitive biomarkers. Changes in presentation and biomarkers led to the development of new diagnostic algorithms. The Minnesota Heart Survey (MHS) and the WHO MONICA study described rigorous classification systems in the 1980’s. Subsequently, the European Society of Cardiology (ESC), the American College of Cardiology (ACC), World Heart Federation (WHF) and the American Heart Association (AHA) developed diagnostic algorithms.
Hypothesis: The diagnostic algorithm selected will strongly influence disease rates.
Methods: All criteria for definite AMI are based on symptoms, biomarkers and ECG changes. However, each available algorithm classifies definite AMI different with subtly different criteria. To determine the magnitude of these differences and the effect of the six algorithms on disease rates, we applied them to a 1995 population-based survey of AMI in the Minneapolis-St. Paul metropolitan area. Adults, age 30 –74, were classified (N=1517).
Results: Disease rates, adjusted for the 2000 census population, ranged from 440 per 100,000 for men and 139 per 100,000 for women (WHO) to 281 per 100,000 for men and 98 per 100,000 for women (MONICA). Other algorithms fell between these two extremes and differed widely.
Conclusions: Application of different diagnostic algorithms results in substantially different AMI rates. These can be critical when describing endpoints for clinical trials, making comparisons between populations or ascertaining trends.