The influence of a history of diabetes on treatment and outcome in acute myocardial infarction, during two time periods and in two different countries

Abstract

Aims: The aim of this study was to investigate the influence of diabetes on treatment and outcome in acute myocardial infarction (AMI), during two time periods, in two countries, and to assess whether this influence has changed over the past decades.

Methods: Patients, aged 30 to 74, with a diagnosis of AMI in two urban areas--Göteborg, Sweden and Minneapolis-St. Paul, Minnesota, USA--hospitalized during 1990-1991 and 1995-1996 were included. The primary endpoint was 7-year all-cause mortality.

Results: The study included 3824 patients, 734 (19%) had diabetes. Age-adjusted in-hospital mortality of diabetic patients was nearly twofold higher compared with non-diabetic patients (9.8% vs. 5.0%, p<0.05). Between 1990-1991 and 1995-1996 in-hospital mortality declined for both diabetic (11.9% vs. 7.6%, p=0.07) and non-diabetic (6.3% vs. 3.6%, p=0.002) patients. A history of diabetes was associated with nearly twofold higher long-term mortality rate (48.5% vs. 26%, p<0.05). Seven-year mortality was reduced between 1990-1991 and 1995-1996 in both diabetic (51.6% vs. 45.2%, p=0.13) and non-diabetic patients (29.3% vs. 22.1%, p<0.0001) (The results did not reach statistical significance for diabetic patients, due to smaller sample size.) During their hospital stay, diabetic patients received significantly less aspirin, beta-blockers and thrombolysis. After adjustment, a history of diabetes remained significantly associated with 7-year mortality following AMI, doubling the hazard of death (hazard ratio (HR)=2.11; 95% confidence interval (CI): 1.80-2.46).

Conclusion: A history of diabetes is associated with nearly twofold higher long-term mortality rate and is independently associated with 7-year mortality following AMI. Short- and long-term mortality decreased from 1990 to 1995 in both non-diabetic and diabetic patients. Underutilization of evidence-based treatments contributes to the remaining increased mortality in diabetic patients with acute coronary disease.