Inter-regional differences and outcome in unstable angina - Analysis of the International ESSENCE trial

Aims Worldwide there is a large Variation in outcome (death, myocardial inf arction and recurrent myocardial infarction) in patients with unstable angi na or non-Q wave myocardial infarction. These variations may be explained b y differences in characteristics of the presenting patients. Here we descri be differences in patient presentation, treatment protocols and outcome and we investigate their relationship using data from the ESSENCE (Efficacy an d Safety of Subcutaneous Enoxaparin in Non-Q-wave Coronary Events) trial. M ethods A total of 2981 patients from six countries which enrolled more than 100 patients were included in the present analysis: United States, Canada, Argentina, France, the Netherlands and United Kingdom. Logistic regression analysis was performed to determine the effect of baseline characteristics on regional outcome. Results At day 30, the lowest triple end-point rate, irrespective of study drug treatment, was noted in the Netherlands (18.9%) and the highest in Arg entina (30.5%). A model including the variables age greater than or equal t o 65 years, prior angina, diabetes, prior aspirin use? ECG changes at basel ine and diagnosis of non-Q wave myocardial infarction and dummy variables f or Argentina and France resulted in concordance of about 60%. Conclusions Inter-regional differences in outcome in unstable angina and no n-Q wave myocardial infarction patients can reasonably well be explained by differences in patient characteristics. However, other so far unidentified variables present in Argentina and France also contributed to differences in outcome and their effect warrants further investigation. (C) 2000 The Eu ropean Society of Cardiology.