Diabetic Women At Risk

Summarized by Robert W. Griffith, MD
January 30, 2006

Introduction

Women usually live longer than men - but not, it seems, if they are both type 2 diabetics. Two earlier studies have suggested that women with type 2 diabetes are at increased risk of fatal coronary heart disease than men, while a third found no difference. Which is right? A large meta-analysis of published studies provides an answer that should be more reliable. It's been published in the British Medical Journal, and we summarize it here.

What was done

The scientists limited their reviews to prospective cohort studies - that is to say, studies in which groups of men and women with diabetes were compared over a period of time with similar groups without diabetes. The estimated risk of death from heart attack in each study had to be adjusted for possible factors that might bias the result - as a minimum, the age of the subjects. In addition, risk factors for coronary heart disease were estimated at baseline for each group (men and women, diabetic and non-diabetic).

What was found

Out of over 5,500 articles that were published, there were 23 publications, which coveried a total of 37 studies, that met the criteria set for analysis. They included information on nearly half a million patients (447,064); of these, almost 25,000 had diabetes at baseline.
The percentages of participants who had fatal heart attacks are given in the table:

	Diabetes	No Diabetes
Women	7.7%	1.2%
Men	4.5%	2.0%
Total	5.4%	1.6%

The overall chance of having a fatal heart attack was, as expected, higher in diabetics - about 3½ times higher. But it was clearly higher for women than men; diabetic women were almost 6½ times more likely to die from a heart attack than non-diabetic women, compared with men's 2¼ times.

Adjusting these values for age and other possible confounding factors - smoking, total cholesterol - did not change the findings substantially. It still emerged that the relative risk for fatal heart attack in diabetics was 50% higher in women than in men.

The analysis of the risk factors at baseline showed that women were already at increased risk before the study began. For instance, the differences in raised systolic blood pressure between diabetic and non-diabetic men and women were 7.8 and 12.5 mmHg, respectively; in other words, women diabetics had, on average, greater increases in blood pressure over non-diabetic women than men diabetics had over non-diabetics. Similarly greater differences (diabetic over non-diabetic) were seen for women with respect to total cholesterol, serum triglycerides, and body mass index (BMI).

What these findings mean

In a nutshell, women with diabetes have a 50% greater chance of dying from a heart attack than men diabetics. Further warning of this difference is provided in the increased cardiac risk factors in women diabetics - higher systolic blood pressure, higher total cholesterol and triglycerides, greater BMI - seen at baseline in the longitudinal studies; some of the studies' follow-up lasted up to 30 years.

The authors give an additional possible reason for this difference between diabetic men and women. They suggest it may reflect a treatment difference that favors men. Recent studies have shown that men with diabetes or coronary heart disease are more likely than women to receive aspirin, statins, or blood pressure medication.

It's obviously necessary to remind women (and their spouses) that women are even more likely than men to die from a heart attack if they are diabetic, and that any cardiac symptoms need to be taken seriously, and acted upon, promptly.

Source

• Excess risk of fatal coronary heart disease associated with diabetes in men and women: meta-analysis of 37 prospective cohort studies. X. Huxley, F. Barzi, M. Woodward, BMJ, 2006, vol. 332, pp. 73--76

Related Links
Women Should Know About Their Early Warning Signs of MI
Statins in Diabetes
AHA: Go Red, for Women
Heart Disease: What Women Need to Know

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