A vascular link: erectile dysfunction may signal glaucoma risk in men

A study¹ from the UK identified an association between the development of primary open-angle glaucoma (POAG) and erectile dysfunction (ED) that is vascular in nature rather than the result of a direct pharmacologic effect, according to the investigators led by medical researcher Ruolan Fan from the Institute of Health Informatics, University College London, London.

The investigators pointed out that while a vascular mechanism has long been proposed since the 1050s² that impairs ocular perfusion and contributes to optic nerve damage, no robust epidemiologic evidence has supported this pathway. However, the hypothesis remains controversial.

Fan and colleagues conducted a prospective, nested, case-control study to determine if the treatment for ED, for which vascular associations have been recognized, is linked to an increased POAG risk in men. However, despite many studies of vascular changes and systemic disease, there is no clarity regarding if the vascular abnormalities precede glaucomatous damage or are secondary from the optic nerve and retinal nerve fiber layer loss, particularly given inconsistent findings from longitudinal studies.^3,4

Study methodology and findings

In this large study, over 200,000 patients who had been diagnosed with glaucoma were matched 4:1 by age and primary care practice to more than 876,000 controls without glaucoma or treatment. The patient data were obtained from two large primary care databases, Clinical Practice Research Datalink (CPRD) Gold and CPRD Aurum, the authors recounted.

The respective mean ages of the cases and controls were 69 and 68 years. ED medications had been prescribed in 20% of the cases vs 17% of the controls. The researchers reported “ED medication use was associated with significantly higher POAG risk (odds ratio [OR], 1.29; 95% confidence interval [CI], 1.25 to 1.32 in CPRD Gold and OR 1.17; 95% CI, 1.15 to 1.18 in CPRD Aurum).”

They also found that older patient age and Black or Asian ethnicity were consistently associated with an increased risk of POAG. Other risk factors included hypertension, diabetes, asthma, migraine, and sickle cell disease, but myocardial infarction and angina were associated with a lower risk.

The current results added to the body of knowledge regarding POAG development. In this study, ED medication use was prospectively associated with a 17% to 29% higher risk of POAG diagnosis. The on-demand nature of ED medication use, the researchers explained, combined with associations with other vascular comorbidities including sickle cell disease, hypertension, and migraine, suggests the link reflects shared vascular pathophysiology rather than a direct drug effect. However, a caveat is that experimental studies that examine the vasoactive medications and POAG outcomes should confirm these findings. Specifically, studies that investigate the effects of vasoactive medications on intraocular pressure and optic nerve perfusion should confirm the mechanistic basis of these associations.

Christopher Owen, PhD, senior author and Professor of Epidemiology in the Population Health Research Institute and Head of Section for Chronic Disease Epidemiology within the School of Health and Medical Sciences, City St George’s, University of London, London, UK, commented, “Our findings strengthen the case that vascular health, not just eye pressure, matters in glaucoma. Understanding this link could help us identify people at high risk sooner and point the way to new treatments that protect from the devastating effect of sight loss caused by glaucoma. The next step is to test whether medicines that act on blood vessels can change the course of the disease.”

References
1. Fan R, Gonzalez-Izquierdo A, Qummer Ul Arfeen M, et al. Br J Ophthalmol. Epub ahead of print. doi:10.1136/ bjo-2026-3301
2. FrancoisJ, NeetensA. Vascularity of the eye and the optic nerve in glaucoma. Arch Ophthalmol. 1964;71:219–25. doi:10.1001/archopht.1964.0097001023501
3. KawasakiR, WangJJ, RochtchinaE, et al. Retinal vessel caliber is associated with the 10-year incidence of glaucoma: the Blue Mountains Eye Study. Ophthalmology. 2013;120:84–90. doi:10.1016/j.ophtha.2012.07.00
4. Ikram MK, Voogd de S, Wolfs RC, et al. Retinal vessel diameters and incident open-angle glaucoma and optic disc changes: the Rotterdam study. Invest Ophthalmol Vis Sci. 2005;46:1182–7. doi: https://doi.org/10.1167/iovs.04-1459