Metformin reduces odds of developing Acute Macular Degeneration among diabetes patients

A recent meta-analysis found that diabetic patients using Metformin have decreased odds of developing age-related macular degeneration (AMD). The study results were published in the journal Investigative Ophthalmology & Visual Science.

Diabetes is commonly treated with Metformin, a biguanide derivative. It exhibits antioxidative, anti-inflammatory, and antiangiogenic activity within the ocular tissue and is hence implicated in the treatment of age-related macular degeneration (AMD). Due to the uncertainty in the past literature, researchers from the U.S.A conducted a systematic review and meta-analysis to establish the conducive effect of metformin usage on AMD. 

Databases like The Ovid MEDLINE/Embase, Cochrane Library, and Web of Science were systematically searched from inception through August 3, 2022. Studies reporting the association between metformin use and odds of AMD were enrolled. Adjusted odds ratios (ORs) of AMD were extracted and random-effects model meta-analysis was used for pooling. Subgroup analyses were conducted based on AMD subtypes, ethnicity, study design, sex, and confirmation of AMD diagnosis.

Findings from the study:

• A total of 9 observational studies with 14,46,284 participants were included in the analysis.
• There was a significant reduction in the odds of AMD with metformin use as shown in the meta-analysis (pooled ORs = 0.81, 95% confidence interval [CI] = 0.70–0.93).
• Metformin use was not significantly associated with dry or wet AMD as per subgroup analysis.
• Significantly lower odds of AMD were especially seen in the Black (pooled ORs = 0.61, 95% CI = 0.58–0.64) and Hispanic populations (pooled ORs = 0.85, 95% CI = 0.81–0.89). 

Thus, the present study was the first of its kind to confirm that oral metformin use was associated with 0.81-fold decreased odds of AMD. But further prospective trials that explore the therapeutic effect of metformin on diabetic patients are needed. 

Further reading: Liang KH, Chen CH, Tsai HR, Chang CY, Chen TL, Hsu WC. Association Between Oral Metformin Use and the Development of Age-Related Macular Degeneration in Diabetic Patients: A Systematic Review and Meta-Analysis. Invest Ophthalmol Vis Sci. 2022;63(13):10. doi:10.1167/iovs.63.13.10