Do Glaucoma, Erectile Dysfunction Have a Common Cause?

Neil Osterweil

February 07, 2012

February 7, 2012 — Men with erectile dysfunction (ED) have a nearly 3-fold greater risk for also having open-angle glaucoma (OAG) than men with normal erectile function, report researchers from Taiwan in an article published in the January issue of Ophthalmology.

A case–control study matching 4605 men with ED with 5 control patients each showed that after controlling for potential confounding factors, men with ED had an odds ratio (OR) for a prior diagnosis of OAG of 2.85 (95% confidence interval [CI], 2.10 - 4.07), write Shiu-Dong Chung, MD, from the Division of Urology at the Far Eastern Memorial Hospital in Taipei, Taiwan, and colleagues.

"Our findings suggest that prospective studies should be undertaken to develop the appropriate clinical guidelines for evaluating concurrent or subsequent ED in OAG patients," they write.

Pathologic mechanisms common to ED and OAG may include the components of the metabolic syndrome (hypertension, decreased insulin sensitivity, dyslipidemia, and obesity) and their effects on inflammatory, vascular, and endocrine abnormalities, the authors suggest.

A urologist who was not involved in the study told Medscape Medical News that the findings implicate OAG as a potential sentinel symptom for vascular disease in men with ED.

"Sometimes men present with no cardiovascular symptoms, but you have to look at them and be concerned that erectile dysfunction is an early symptom of risk for cardiovascular disease such as coronary disease, metabolic syndrome, diabetes mellitus, hypertension — the whole 9 yards. Now adding to that list would be the concern that men with erectile dysfunction also may have a higher incidence of open-angle glaucoma," said Joseph F. Harryhill, MD, assistant professor of surgery in the Division of Urology at the University of Pennsylvania School of Medicine in Philadelphia.

The study suggests that OAG and ED appear to have a common mechanism of endothelial dysfunction related to nitric oxide.

For their study, the investigators drew on longitudinal data from a health insurance database to identify 4605 men older than 40 years who had newly diagnosed ED (International Classification of Diseases, Ninth Revision, Clinical Modification, code 607.84), as well as 23,025 control patients (5 for each case patient). The control patients had no diagnosis of either psychogenic or organic ED, and were matched to case patients by age group and index date.

OAG case patients were identified as those patients with an OAG diagnostic code (365.1 or 365.11) made before the index ED date who had been prescribed topical antiglaucoma medications.

A diagnosis of OAG was found in 53 case patients (1.1%) and 84 control patients (0.4%). In covariate analysis adjusting for age, income, geographic location, and metabolic syndrome components, ED was significantly associated with hyperlipidemia (adjusted OR, 1.43; 95% CI, 1.32 - 1.55), diabetes (adjusted OR, 1.33; 95% CI, 1.23 - 1.45), hypertension (adjusted OR, 1.70; 95% CI, 1.58 - 1.83), and coronary heart disease (adjusted OR, 1.23; 95% CI, 1.13 - 1.34; all P < .001).

"To our knowledge, this is the first study to document the association between ED and OAG based on a population-based dataset. This finding suggests that there may be a common mechanism of disease for ED and OAG, which is not entirely explained by the variables included in the multiple logistic model," the authors write.

They note that hyperglycemia and insulin resistance, 2 primary components of the metabolic syndrome, can cause chronic inflammation that in turn can damage vascular endothelia and lead to atherosclerosis. Chronic inflammation has also been linked to glaucoma in recent studies, they note.

Dr. Harryhill said that he and his colleagues do not routinely ask patients with ED whether they have been diagnosed with OAG or elevated intraocular pressure, but that they are always on heightened alert for other signs of potential vascular disease in such patients.

"If this research pans out and it turns out that there is a strong link between these 2 conditions, maybe we should tell patients that they have an increased risk of having this problem and have their intraocular pressures checked," he said.

The authors and Dr. Harryhill have disclosed no relevant financial relationships.

Ophthalmology. 2012;119:289-293. Abstract