Study: Some Vasodilators May Increase Risk of Macular Degeneration
Beta blockers are also implicated
There may be a connection between taking vasodilators and developing early-stage age-related macular degeneration (AMD), the leading cause of vision loss and blindness among Americans 65 years of age and older, according to a new study published online in Ophthalmology.
AMD — the deterioration of the eye’s macula, which is responsible for the ability to see fine details clearly — affects an estimated 11 million people in the U.S. In addition to increased age, the development of AMD may be attributed to several risk factors, including hereditary risk and smoking. Some studies have also found an association between AMD and hypertension, but these findings have been inconsistent.
To help clarify the relationship between the incidence of AMD and the use of blood pressure-lowering drugs, including vasodilators, researchers at the University of Wisconsin School of Medicine and Public Health conducted a long-term population-based cohort study of nearly 5,000 residents of Beaver Dam, Wisconsin (aged 43 to 86 years) from 1988 to 2013. The research was part of the National Eye Institute-funded Beaver Dam Eye Study, which has collected information on the prevalence and incidence of AMD, macular degeneration, and diabetic retinopathy since 1987.
The researchers found that, after adjusting for age, sex, and other factors, the use of a vasodilator was associated with a 72% greater risk of developing early-stage AMD. Among people who were not taking vasodilators, an estimated 8.2% developed signs of early AMD. In comparison, among those taking a vasodilator medication, 19.1% developed the disease.
The researchers also found that taking oral beta blockers, such as atenolol (Tenormin) and metoprolol (Lopressor), was associated with a 71% increase in the risk of neovascular AMD, a more advanced and vision-threatening form of the disease. Among those who were not taking oral beta blockers, an estimated 0.5% developed signs of neovascular AMD. In comparison, among those taking oral beta blockers, 1.2% developed neovascular AMD.
While the new study provides risk estimates of associations between blood pressure-lowering medications and AMD at various stages, the researchers caution that their study was not able to discern the effects of the medications themselves and the conditions for which participants were taking those medications.
“As significant as these results may be, it’s important that they be replicated first, and if possible, tested in a clinical trials setting before changing anyone’s medication regimens,” said lead investigator Ronald Klein, MD, MPH. “Further research is needed to determine the cause of these increased risks.”
Source: American Academy of Ophthalmology; May 28, 2014.