People with diabetes have the same high risk for MI, stroke or cardiovascular (CV) death as nondiabetics who’ve already had a heart attack, according to a large study published online March 31 in Circulation: Journal of the American Heart Association.
“The increased risk was observed in people at all ages with either Type 1 or Type 2 diabetes who were receiving insulin or other drugs to reduce levels of sugar in the blood,” said lead author Tina Ken Schramm, MD, research fellow at the Gentofte Hospital in Hellerup, Denmark. “When people with diabetes do have heart attacks, they are twice as likely to die as non-diabetics.”
“Now I think we should be saying ‘the sooner, the better’ for primary prevention of cardiovascular diseases in diabetics,” Schramm said.
In the population study of 3.3 million people age 30 and older living in Denmark in 1997, 71,801 people had diabetes and 79,575 had a previous MI, according to researchers. Over a follow-up period of five years, the investigators identified deaths from a central population register and causes of death were obtained from a national register.
Schramm and colleagues examined diagnoses from a national patient registry and information on medication was obtained from registries on claimed prescriptions in the national pharmaceutical database. Due to the national registries in Denmark and the possibility of cross-linkage of all registries, it was possible to study a totally unselected population, including all patients with diabetes receiving glucose-lowering medication, Schramm said.
In Cox-proportional regression analyses, the researchers said that the relative risk of dying from CV disease was 2.45 times greater for women with diabetes compared with 2.62 times greater for women with a prior MI. The relative risk of dying from CV causes in men with diabetes was 2.42 times higher compared with a 2.44 hazard ratio in men with prior MI, according to the investigators.
For the composite of MI, stroke and death from CV disease, the researchers said the hazard ratios in men with diabetes were 2.32 vs. 2.48 for men who had at least one heart attack. For women with diabetes, the relative risk of the combined end point of MI, stroke or CV death was 2.48 and those with a history of MI faced a hazard ratio of 2.71, the authors wrote.
The researchers said “the major finding of this study is that all patients age 30 and older who require glucose-lowering treatment are at a particularly high risk of cardiovascular death and disease, comparable to that of non-diabetics with a prior heart attack, regardless of sex and diabetes type.”
Schramm noted that they were unable to study patients on diet-only treatment, a limitation of the study. Moreover, the researchers said they could not precisely differentiate between Type 1 and Type 2 diabetes patients and could not adjust for several well-known risk factors including high blood pressure, high cholesterol, obesity, smoking, physical activity and blood glucose levels.
Based on the study results, Schramm and colleagues wrote that all people with diabetes who are receiving glucose-lowering therapy should talk to their physicians about being started on daily aspirin therapy, as well as treatment with cholesterol-lowering drugs known as statins and possibly blood pressure-lowering drugs called ACE-inhibitors. Also, the treatments, which are effective heart attack prevention strategies, should be also considered in the younger age groups of these diabetes patients, the researchers said.
The Danish Pharmacist Foundation funded the study.