UK study: Diabetes increases risk of heart attack death. Here are the surprising details.
Diabetes increases the risk of heart attack death by 50%, according to a study published in the Journal of Epidemiology and Community Health.
Researchers from Leeds Institute of Cardiovascular and Metabolic Medicine at the University of Leeds in the UK collected patient data from the Myocardial Ischaemia National Audit Project (MINAP), a comprehensive registry of hospitalizations for acute coronary syndrome in England and Wales. The study included more than 700,000 people who were admitted following AMI from January 1, 2003 through June 30, 2013. Of these, 121,000 had diabetes.
Previous studies had found a connection between diabetes and decreased survival following acute myocardial infarction (AMI); however, the majority of these studies considered all cause-mortality as the primary outcome, which does not allow an accurate evaluation of the burden of AMI in patients with diabetes. In order to estimate the long-term excess mortality associated with diabetes among patients with an AMI, the researchers of this study chose to measure relative survival from hospitalization.
Of the patients who were enrolled in the study, about 40% were admitted following STEMI (ST-elevation myocardial infarction) and 60% were admitted following NSTEMI (non-ST-elevation myocardial infarction). In total, there were 120,568 patients who were also diagnosed with either type 1 or type 2 diabetes mellitus (12.1% of STEMI patients; 20.4% of NSTEMI patients). Survival time for patients was calculated from date of hospitalization to date of death, date of last information available, or end of the study.
After adjusting for age, sex and year of AMI, co-morbidities and hospital treatments for heart attack, the researchers found differences in survival rates. Patients with diabetes were 56% more likely to die after STEMI and 39% more likely to die after NSTEMI, compared to people without diabetes. The effect was similar among all diabetes patients, including patients who were newly diagnosed without treatment, those using dietary control, as well as patients on insulin, oral medications, or both. Furthermore, the effect of diabetes on mortality remained stable during the entire study from 2003 to 2013.
“These results provide robust evidence that diabetes is a significant long-term population burden among patients who have had a heart attack,” Chris Gale, PhD, a consultant cardiologist and associate professor in the School of Medicine at the University of Leeds in the UK, said. “Although these days people are more likely than ever to survive a heart attack, we need to place greater focus on the long-term effects of diabetes in heart attack survivors.”
Next, the researchers will study exactly why people with diabetes have a higher risk of death after a heart attack, because the study could not show a cause-and-effect relationship.