Diabetes Medication with age related eye disorders linked together

Although diabetes was clearly associated with cataracts, diabetes medication was not. This has been suggested by a recent study published in JAMA Opthalmology.

Recent studies suggest that the diabetes drug metformin has a protective effect on open-angle glaucoma (OAG) and age-related macular degeneration (AMD). However, studies have not addressed the critical issue of confounding by indication, and associations have not been evaluated in a large prospective cohort.

The aim of this study conducted by Joëlle E. Vergroesen et. al was to determine the association between metformin and other diabetes medication with open-angle glaucoma,age-related macular degeneration, and cataracts in the large, prospective, population-based Rotterdam Study.

"We also examined the association between untreated T2D with these eye diseases to investigate potential comorbidity. The longitudinal study design allowed us to determine T2D and medication use before the onset of eye disorders and provided the potential to study their cumulative lifetime risks," the authors wrote.

This cohort study included participants from 3 independent cohorts from the prospective, population-based Rotterdam Study between April 23, 1990, and June 25, 2014. Participants were monitored for incident eye diseases and had baseline measurements of serum glucose. Data on diabetes medication use and data from ophthalmologic examinations were gathered. The exposures given were Type 2 diabetes (T2D) and the diabetes medications metformin, insulin, and sulfonylurea derivatives.           

Type 2 diabetes was diagnosed in 28.4% of participants, open-angle glaucoma was diagnosed in 4.4%participants, age-related macular degeneration was diagnosed in 17.6% of participants, and cataract was diagnosed in 37.3% of participants. Untreated Type 2 diabetes was associated with a higher risk of open-angle glaucoma

age-related macular degeneration, and cataracts. T2D treated with metformin was associated with a lower risk of open-angle glaucoma. Other diabetes medication was associated with a lower risk of age-related macular degeneration. The cumulative lifetime risk of open-angle glaucoma was lower for individuals taking metformin than for individuals without T2D; the lifetime risk of age-related macular degeneration was lower for individuals taking other diabetes medication.

The authors concluded that Treatment with metformin was associated with a lower risk of open-angle glaucoma, and other diabetes medication was associated with a lower risk of age-related macular degeneration. Proof of benefit would require interventional clinical trials.