Diabetes appears to rob women of usual advantage in heart disease risk

For men, a heart attack increases the risk of dying from coronary heart disease more than diabetes does, but for women, diabetes is sometimes the greater threat, according to a new study (PDF) in the May 3, 2005, issue of the Journal of the American College of Cardiology.

“In women, prior diabetes at baseline has a greater risk of coronary heart disease mortality than prior heart attack, but a heart attack that occurs during follow-up has a greater risk than diabetes that develops during follow-up. More aggressive management of diabetes to prevent cardiovascular disease may be needed, particularly in women,” said Gang Hu, M.D., Ph.D., at the National Public Health Institute and University of Helsinki in Finland.

The researchers looked at data from large population surveys in Finland. In the first analysis, they compared the outcomes of men and women who reported having had a heart attack or prior diabetes at the time of the baseline survey. This group included 2,416 participants and the average follow-up period was 12 years.

The second analysis looked at what happened to men and women who had a heart attack or developed diabetes during the follow-up period. This group was made up of 4,315 participants and had an average follow-up period of almost eight years.

The researchers pointed out that most previous studies of the effects of heart attacks and diabetes have not paid attention to when a heart attack occurred or how long patients had diabetes.

“In men, heart attack at baseline or during the follow-up is associated with a greater risk on coronary heart disease mortality than seen with diabetes. In women, prior heart attack at baseline increases the risk of coronary heart disease mortality less than prior diabetes does, but incident heart attack during follow-up has a greater risk than incident diabetes. In general, diabetes is bad news for women,” Dr. Hu said.

“The results of our study have important implications for clinical practice: first, we need to consider carefully the treatment strategies on individual disease status, particularly type 2 diabetes in women, for future cardiovascular disease risk. Furthermore, in order to reduce cardiovascular disease mortality, more active management and prevention of diabetes are needed,” the researchers wrote.

Although the researchers observed clear gender differences in the risk of death from coronary heart disease, rates of death from all causes were similar for both men and women with diabetes or heart attack that occurred during follow-up.

“The major cause of death for subjects with incident heart attack is coronary heart disease, but the subjects with incident diabetes may increase their risk of death from coronary heart disease, stroke, cancer, kidney disease, infections and other reasons. Thus, total mortality is similar between subjects with incident diabetes and heart attack, showing the significance of diabetes on overall health,” Dr. Hu explained.

Dr. Hu noted that the researchers did not have any data on what sort of drug treatment patients received and they did not have measurements of blood glucose levels.

Charles M. Alexander, M.D., at Merck in West Point, Penn., who was not connected with this study, said it supports the conclusions of earlier work on diabetes and heart attacks.

“Seven years ago, Haffner and colleagues concluded in an article published in the New England Journal of Medicine that people with diabetes had the same risk for subsequent heart attack as those who had had a prior heart attack. The results of that study were not universally accepted, and some subsequent articles cast doubt on Haffner's conclusion. The article by Hu et al. confirms the original conclusions of Haffner's study and provides a better understanding of the gender differences that help to explain the apparent inconsistencies,” Dr. Alexander said.

Christiane E. Angermann, M.D., at the University of Würzburg, Germany, who also was not connected with this study, adds more evidence to the understanding of how the impact of diabetes and heart attacks differs in men and women.

“Thus, this study provides yet another strong argument for the necessity to consider gender-related differences between men and women regarding the impact of risk factors, while designing guidelines not only for diagnosis and therapy, but also, and in particular, for the prevention of cardiovascular disease,” Dr. Angermann said.

Dr. Angermann added that it is important to also consider gender-related aspects of treatment, which were not part of this study.

The American College of Cardiology, a 31,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.

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