Glucose-lowering medications protect against glaucoma, AMD

While diabetes is a risk factor for cataract, glucose-lowering medications appear to have a protective effect on the risks of open-angle glaucoma (OAG) and age-related macular degeneration (AMD), as shown in a study.

The study included 11,260 participants (mean age 65.1 years, 58.7 percent women) across three independent cohorts from the prospective, population-based Rotterdam Study. All participants were monitored for incident eye diseases (ie, OAG, AMD, cataract) and had baseline measurements of serum glucose.

Researchers collected data on glucose-lowering medication use, including metformin, insulin, and sulfonylurea derivatives. They performed multivariable logistic regression analyses to evaluate the association of various diabetes medications with eye diseases.

A total of 2,406 (28.4 percent) patients had T2D. OAG was diagnosed in 324 of 7,394 participants (4.4 percent), AMD in 1,935 of 10,993 participants (17.6 percent), and cataract in 4,203 of 11,260 participants (37.3 percent). Untreated T2D conferred a higher risk of OAG (odds ratio [OR], 1.50, 95 percent confidence interval [CI], 1.06–2.13; p=0.02), AMD (OR, 1.35, 95 percent CI, 1.11–1.64; p=0.003), and cataract (OR, 1.63, 95 percent CI, 1.39–1.92; p<0.001).

On the other hand, treatment with metformin exerted a protective effect on the risk of OAG (OR, 0.18, 95 percent CI, 0.08–0.41; p<0.001), while other diabetes medications (ie, insulin, sulfonylurea derivates) were associated with a lower risk of AMD (combined OR, 0.32, 95 percent CI, 0.18–0.55; p<0.001).

The cumulative lifetime risk of OAG was notably lower among individuals taking metformin than among those without T2D (1.5 percent vs 7.2 percent). A similar pattern was observed for the lifetime risk of AMD, which was lower among individuals taking other diabetes medications vs those without T2D (17.0 percent vs 33.1 percent).

Interventional clinical trials are needed to establish the benefit of glucose-lowering drugs on the risks of eye diseases.