Diabetes Awareness Among Coronary Artery Disease Patients Is Higher in Women Than in Men

The risk of diabetes complications can be attenuated by appropriate diabetes management. Unfortunately, many patients with type 2 diabetes mellitus (T2DM) are unaware of their condition (1) and therefore cannot receive appropriate treatment.

Diabetes in various populations is similarly prevalent in men and women, but important sex differences exist with regard to the impact of diabetes on patient outcomes (2). In this context, it appears important to understand how diabetes awareness, i.e., the proportion of patients with diabetes knowing that they have the condition, differs between men and women. Importantly, sex differences in diabetes awareness have not yet been investigated in the extremely high-risk patients with both T2DM and established coronary artery disease (CAD).

We therefore investigated 1,209 unselected consecutive Caucasian patients, 422 women and 787 men, who were referred to coronary angiography for the evaluation of established or suspected stable CAD. Patients with type 1 diabetes (C-peptide negative) were not enrolled. A total of 292 women and 706 men had CAD at angiography and were included in the present analysis.

Overall, 114 women and 288 men had T2DM according to American Diabetes Association criteria; diabetes prevalence did not significantly differ between women and men (32.2 vs. 27.3%; P = 0.125). In those with diabetes, the condition was newly diagnosed in 17.5% (n = 20) among women and in 33.0% (n = 95) among men. Thus, diabetes awareness, i.e., the proportion of previously diagnosed diabetes, was significantly higher in women than in men (82.5 vs. 67.0%; P = 0.002).

Table 1 compares characteristics of women and of men who were aware of their condition to those in whom diabetes was newly diagnosed. Both among women and among men, those who were aware of having diabetes were younger and had higher HbA_1c and fasting glucose and lower LDL cholesterol. The use of ACE inhibitors/angiotensin receptor blockers was higher in women with T2DM aware of having diabetes.

In logistic regression analysis, female sex was strongly associated with diabetes awareness univariately (odds ratio [OR] 2.31 [95% CI 1.34–3.97]; P = 0.002), after adjustment for age (OR 2.76 [95% CI 1.57–4.82]; P < 0.001), after additional adjustment for HbA_1c as well as fasting glucose (OR 2.96 [95% CI 1.60–5.45]; P = 0.001), and after further adjustment for hypertension, total cholesterol, and LDL cholesterol, i.e., for all variables that either among women or among men differed between those aware and those unaware of having diabetes (OR 3.39 [95% CI 1.77–6.51]; P < 0.001).

Our observations for the first time show that among patients with established CAD, diabetes awareness is higher in women than in men and that female sex is an independent predictor of diabetes awareness in these extremely high-risk patients.

This finding is clinically important. Given the preponderance of male sex in CAD populations, the majority of CAD patients with T2DM are men, many of whom have undiagnosed diabetes. Microvascular diabetes complications can largely be prevented by lowering HbA_1c values <7.0% (3). The mean HbA_1c among our patients unaware of having diabetes was 6.6%, but still approximately one out of five patients had HbA_1c values ≥7.0%. Considering macrovascular complications, glucose-lowering treatments are available that improve cardiovascular outcomes in patients with established CAD that are recommended in current guidelines (4) but that patients with diabetes not diagnosed as such will not receive. Further, the American Association of Clinical Endocrinologists guidelines already demand a very low LDL cholesterol goal of <55 mg/dL in patients with CAD plus diabetes compared with <70 mg/dL in those with CAD only (5).

In conclusion, in light of our observations, increasing diabetes awareness in CAD patients appears warranted, especially among men.