The disparity between long-term survival in patients with and without diabetes following a first myocardial infarction did not change between 1989 and 2006: an analysis of 6,776 patients in the Northern Sweden MONICA Study

Abstract

Aims/hypothesis: Long-term survival after myocardial infarction (MI) has improved in the population, but data on diabetic patients is lacking. We analysed survival for up to 18 years after a first MI in patients with or without diabetes.

Methods: The Northern Sweden MONICA Myocardial Infarction Registry was linked to the Cause-of-Death Registry for a total of 6,776 patients, 25-64 years of age, with a first MI during 1989-2006. Prehospital deaths were included. Follow-up ended on 30 August 2008.

Results: Sixteen per cent had diabetes. Median follow-up time was 6.8 years, and the study included 50,667 patient-years. One third of the non-diabetic patients died vs half of the diabetic patients. Median survival for non-diabetic men was 227 months and for diabetic men 123 months. Corresponding figures for the non-diabetic and diabetic women were 222 and 81 months respectively. Men with diabetes had an age-adjusted HR for all-cause mortality of 1.56 (95% CI 1.39, 1.79) vs men without diabetes. Mortality risk was higher among diabetic women, HR 1.97 (1.62, 2.39) (diabetes × sex interaction, p = 0.03). Survival increased for three consecutive cohorts and was higher in non-diabetic patients for all durations of follow-up and in all three cohorts. The interaction of diabetes x cohort was not significant over time (p = 0.5) and HRs did not differ either.

Conclusions/interpretation: Long-term survival after a first MI is markedly lower in diabetic patients, especially among women, over an 18-year observation time. Although survival has improved in diabetic patients, the effect of diabetes upon mortality has not diminished.