Researchers at the University of Leeds tracked 700,000 people, who had been admitted to hospital with a heart attack between January 2003 and June 2013. Of these, 121,000 had diabetes.
After stripping out the effects of age, sex, any other illnesses and differences in the emergency medical treatment received, the team found stark differences in survival rates.
People with diabetes were 56 per cent more likely to have died if they had experienced a ST elevation myocardial infarction (STEMI) heart attack - in which the coronary artery is completely blocked - than those without the condition.
They were 39 per cent more likely to have died if they had a non-ST elevation myocardial infarction (NSTEMI) heart attack - in which the artery is partially blocked - than those without diabetes.
Lead researcher Dr Chris Gale said that these results provide robust evidence that diabetes is a significant long-term population burden among patients who have had a heart attack.
He added that the next step in their research would be finding out exactly what it is about having diabetes that increases the risk of death following heart attack.
Dr Mike Knapton, Associate Medical Director at the British Heart Foundation, which funded the study, said: "This research highlights the need to find new ways to prevent coronary heart disease in people with diabetes and develop new treatments to improve survival after a heart attack."
The study is published in the Journal of Epidemiology and Community Health.