Aim: To investigate the differences in treatment of acute myocardial infarction (AMI) between different hospitals within one country, and the causes of these differences.
Method: The Register of Information and Knowledge about Swedish Heart Intensive care Admissions recorded every CCU admitted patient in 67 hospitals 1999-2000. The use often generally recommended treatments and examinations in patients with AMI were compared between the hospitals after 23 different background characteristics were encountered for by propensity score analyses.
Results: 32954 primary admissions for AMI were included. After adjustment for patient characteristics there were few significant deviations between hospitals in the proportion treated with acute reperlusion, aspirin, beta-blockade or ACE-inhibition at discharge. There were, however, 3 to more than 10 fold differences between hospitals in the proportion of patients treated with intravenous B-blockers, intravenous nitroglycerin, intravenous or subcutaneous anticoagulants, and discharge lipid lowering medication and even larger discrepancies in the use of in echocardiography and coronary angiography. There was a significant (r=0.668;p<0.001) correlation between hospital average rank between the years but no correlation between hospital size and the hospital's average rank for the adjusted use of these treatments (r-0.003 and p=0.98).
Conclusion: After differences between the patients background characteristics and chance findings have been taken into account, most hospitals provide similar regimens concerning treatment modalities where there is strong evidence for efficacy. The remaining large treatment variations mainly concern treatment where the indications and evidence are in development or where uncertainties remain or where there are differences in immediately available treatment facilities. In order to ascertain the quality and equality of treatment in acute myocardial infarction continuous quality control of treatments and outcomes are essential especially in areas with a rapid development of new treatments and in centres with limited resources.