Open-angle glaucoma (OAG) and age-related macular degeneration (AMD) are ocular disorders not typically related to type 2 diabetes (T2D). However, inflammation can play a role in any of these diseases, and a new analysis suggests that metformin reduces the lifetime patient risk of developing OAG for those with T2D. Other prescriptions — insulin and those in the sulfonylurea class — can decrease the risk of AMD, according to a report published in JAMA Ophthalmology.

The study included 11,260 participants who completed baseline serum glucose tests, ophthalmic exams, and had uninterrupted prescription records. Participants’ mean age was 65.1 years, and T2D was present in 28.4% of the total. The prospective investigation was designed to remove confounding by indication: researchers first calculated the association of T2D with ocular disorders, and then determined whether there was a link between insulin-managing medications and onset of OAG, AMD, and cataracts.

OAG was exhibited in 4.4% of the overall eligible sample, as well as in 7% with untreated T2D, and 1% of those with diabetes who received metformin


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AMD was present in 17.6% of the total studied, in 20.0% of individuals with untreated T2D, and 14% of those with T2D who took metformin. 

Cataracts were experienced by 37.3% of the population, 45.6% of those with untreated diabetes, and 45.1% of patients with hyperglycemia using metformin.

Untreated patients had a significantly greater risk to develop cataract (P <.001), open-angle glaucoma (P =.02), or AMD (P =.003). Metformin use was associated with lower risk for OAG (P <.001), and AMD (P <.04), compared with untreated patients. Other diabetes drugs, sulfonylurea derivatives and insulin, were associated with reduced risk of AMD (P <.001). In fact, individuals using sulfonylurea had lower lifetime risk to acquire AMD than any other group, including patients without T2D, the report shows.

A limitation was the population-based design that by nature may lessen the proportion of those with OAG who are also taking metformin. Additionally, 98% of the participants were of European ancestry. Strengths consisted of a large sample and longitudinal design, along with data adjusted for statin, tobacco, and antihypertensive use.

Disclosures: One study author declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

Vergroesen JE, Thee EF, Ahmadizar F, et al. Association of diabetes medication with open-angle glaucoma, age-related macular degeneration, and cataract in the Rotterdam studyJAMA Ophthalmol. Published online May 19, 2022. doi:10.1001/jamaophthalmol.2022.1435