Inhibiting AMD

Though acetylcholinesterase inhibitors (AChEIs) are already commonly used to improve the quality of life for those suffering with Alzheimer’s disease (AD), reports suggest that these inhibitors could also possess secondary health benefits outside of dementia treatment (1). Examining the potential ophthalmic benefits of the drugs, researchers looked at how the inhibitors might reduce incidence of age-related macular degeneration (AMD) in those living with Alzheimer’s disease (2).

“We believe AMD may be linked to neuroinflammatory processes in the macula,” explains Scott Sutton, a clinical researcher at the Dorn Research Institute/Veterans Affairs Medical Center and one of the study authors. “Preclinical studies [...] from other research groups have noted that AChEIs may have the ability to mitigate neuroinflammation, leading us to hypothesize that patients with AD treated with AChEIs may have a reduced risk of developing AMD.”

For the large-scale retrospective study, patient data was taken from healthcare facilities of the US Department of Veterans Affairs over a 23-year period. In this case, the cohort involved a total of 21,823 veterans, aged between 55 and 80, who had been diagnosed with Alzheimer’s disease but had no pre-existing AMD diagnosis. The study found that those in the AChEIs treatment group resulted in a 6 percent lesser incidence of AMD when compared with untreated patients.

“Our findings demonstrated a small reduction in the risk of AMD among patients with AD receiving AChEIs,” confirms Sutton. However, treatment allocation was not randomized, which could introduce the possibility of selection bias and confounding factors, Sutton acknowledges. “Moreover, because the control group was untreated, confounding by indication is a concern,” he says. “Although we cannot fully rule out confounding by indication, we attempted to balance patient characteristics to minimize the bias.”

Sutton says the next steps would be a randomized clinical trial to determine if there is a cause-and-effect relationship between the inhibitors and reduced incidence of AMD, as well as investigating the genetic predisposition for AMD to confirm the effect of the inhibitors. He also suggests that further research could include more diverse demographics.

This article first appeared in The New Optometrist.