BERKELEY, CA (UroToday.com) - Cardiovascular disease (CVD) is the main cause of death in patients with diabetes, so its early detection is extremely important. Diabetic men have a higher prevalence of ED compared with the general population, and the prevalence of ED increases with age along with the duration and severity of the diabetes.
Several recent studies have shown that ED is associated with the risk of cardiovascular events (CV events), however, a meta-analysis of the overall risk of CV events associated with ED in diabetic patients whose CVD risk is far greater than that of non-diabetic patients has not yet been performed.
In this article, we conducted a meta-analysis to clarify the association between ED and CV events in diabetic men. We searched MEDLINE and the Cochrane Library for pertinent articles, including references, published between 1951 and 2012.
A total of 3 791 CV events were reported in 3 cohort studies and 9 cross-sectional studies (covering 22 586 subjects). Across the cohort studies, the overall odds ratio (OR) of diabetic men with ED versus those without ED was 1.74 (95% confidence interval [CI]: 1.34–2.27; P < 0.001) for CV events and 1.72 (95% CI: 1.5–1.98; P < 0.001) for coronary heart disease (CHD). Moreover, a meta-regression analysis found no relationship between the method used to assess ED (questionnaire or interview), mean age, mean hemoglobin A1c, mean body-mass index, or mean duration of diabetes and the risk of CV events or CHD. In the cross-sectional studies, the OR of diabetic men with ED versus those without ED was 3.39 (95% CI: 2.58–4.44; P < 0.001) for CV events (N = 9), 3.43 (95% CI: 2.46–4.77; P < 0.001) for CHD (N = 7), and 2.63 (95% CI: 1.41–4.91; P = 0.002) for peripheral vascular disease (N = 5).
Diabetic men with ED suffer a significant decline in quality-of-life measures, but their symptoms may remain undetected because many physicians do not inquire about sexual health. It has been reported that the majority of men with diabetes and ED have never been asked about their sexual function by their physicians, and therefore do not receive treatment for ED. Our findings suggest that ED could be a marker of silent CVD and that silent CVD should be excluded before beginning ED treatment.
Several mechanisms attempting to explain the association between ED and CVD have been postulated. One is the “artery size hypothesis.” Atherosclerosis affects all major vascular beds to a similar extent, but the penile arteries have a smaller diameter than the coronary arteries (1–2 mm vs. 3–4 mm) and thus are affected earlier by accumulation of atherosclerotic plaque, so that the onset of ED may precede cardiovascular events. Another possible explanation is that endothelial dysfunction may be a shared etiologic factor for both diseases. Endothelial dysfunction without atherosclerotic narrowing of the penile arteries will more likely cause ED than angina if the coronary arteries were similarly affected. There may also be smooth muscle dysfunction as well as endothelial dysfunction in patients with ED, which could occur before the onset of systemic vascular disease. Moreover, ED is a major clinical manifestation of diabetic autonomic neuropathy. Autonomic neuropathy impairs cholinergic activation of the erectile process and interferes with autonomic pelvic nerve stimulation and/or the corporal nerve`s release of endogenous neurotransmitters.
Recently, there have been many reports about the usefulness of CVD screening in asymptomatic diabetic patients. Type 2 diabetes is associated with an elevated risk of coronary artery disease, but patients are often asymptomatic and therefore the exact value of screening this patient group has yet to be fully elucidated.
We believe that capturing a complete and accurate history of sexual function, hypertension, dyslipidemia, as well as establishing family history of CVD will all help improve the risk assessment of coronary heart disease.
In conclusion, our findings should prompt physicians to inquire with their diabetic male patients about ED. In addition, the relationship between ED and CVD should be further investigated and researched with well-designed and carefully controlled cohort studies in order to confirm whether the identification of ED facilitates the early detection of diabetes in men with a high risk of CVD.
Written by:
Tomohide Yamada, MD, PhD student as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
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