Diabetes as Risk Factor for Incident Coronary Heart Disease in Women Compared With Men: A Systematic Review and Meta-Analysis of 64 Cohorts Including 858,507 Individuals and 28,203 Coronary Events

Study Questions:

Does the cardiovascular disease risk associated with diabetes differ for women compared to men?

Methods:

This meta-analysis used PubMed to identify prospective population-based cohort studies published between January 1, 1966 and February 13, 2013. Studies were eligible if they reported sex-specific relative risks (RRs) for incident coronary heart disease (CHD) associated with diabetes. Studies were excluded if they had not adjusted for at least age or did not provide information on the variability around the point estimate. Random-effects meta-analyses with inverse variance weighting were used to obtain sex-specific RRs and the RR ratio (RRR) (women: men) for incident CHD associated with diabetes.

Results:

Of the 8,183 articles that were identified through the systematic search, 116 articles qualified for full-text evaluation. Of these, 18 articles provided information on sex differences in the association between diabetes and risk of CHD. Overall, data from 64 cohorts, including 858,507 individuals (42% women) and 28,203 incident CHD events, were available. Thirty cohorts were from Asia (55% of the individuals); 13 from Europe (23%); 11 from Australia, New Zealand, or Pacific (12%); and 10 from the United States (10%). Individuals were between 20 and 107 years of age at baseline and the duration of follow-up ranged from 5 to 30 years. The average prevalence of diabetes at baseline was 3.4% among women and 4.8% among men. The RR for incident CHD associated with diabetes compared with no diabetes was 2.82 (95% confidence interval [CI], 2.35-3.38) in women and 2.16 (95% CI, 1.82-2.56) in men. The multiple-adjusted RRR for incident CHD was 44% greater in women with diabetes than in men with diabetes (RRR, 1.44; 95% CI, 1.27-1.63) with no significant heterogeneity between studies (I2 = 20%).

Conclusions:

The authors concluded that women with diabetes have more than a 40% greater risk of incident CHD compared with men with diabetes. Sex disparities in pharmacotherapy are unlikely to explain much of the excess risk in women, but future studies are warranted to more clearly elucidate the mechanisms responsible for the substantial sex difference in diabetes-related risk of CHD.

Perspective:

These data support prior studies, which have suggested an increased risk for CHD associated with diabetes among women. Understanding the biology behind this difference would be informative for the CHD prevention strategies in women.

Keywords: New Zealand, Coronary Artery Disease, Australia, Diabetes Mellitus, Type 2, Risk Factors, Europe


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