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Andrea Blitzer, Sandra Ham, Dimitra Skondra MD,PhD; Metformin use reduces the risk of age-related macular degeneration. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2316.
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The common anti-diabetic drug metformin has been shown to have protective effects against many age-related diseases like cardiovascular diseases and cancer. The purpose of this study is to investigate if metformin has a protective effect against the development of age-related macular degeneration (AMD).
We conducted a case-control study of the association of metformin use and AMD using data from the IBM MarketScan 2006 to 2017 Commercial and Medicare Supplemental Databases. These databases represent the health services of approximately 185 million people in the United States with employer-sponsored health insurance. Using ten years of claims data from MarketScan, we identified AMD patients based on ICD-9 and ICD-10 diagnosis codes. We matched these patients to controls by age, Charlson Comorbidity Index, anemia, hypertension, region of the US, and year of eye exam. Two controls were selected for each case. Pharmacy claim data were used to identify metformin usage. The final sample had 311,124 cases of AMD with 621,768 controls for 932,892 patients total.
We found that in unadjusted bivariate analyses, patients who used metformin during the two years prior to “index date” of new AMD diagnosis, had a 5% reduction in risk of AMD compared with patients who did not use metformin (OR: 0.95 CI 0.94-0.96). Those who used a total of 1-270 g/2 years had 10% reduced risk of developing AMD (OR=0.91, CI 0.89-0.94). In stratified logistic regression models adjusting for risk factors and other medication use, the beneficial effect of metformin persisted (OR=0.96, CI 0.94-0.98). The associations remained stable with increasing dose up to >1080 g/2 years (OR=0.98, CI 0.95-1.01). For 1-270 g/2 years, OR=0.96 (CI 0.94-0.99); 271-600 g/2 years, OR=0.95 (CI 0.92-0.97); 600-1080 g/2 years, OR=0.96 (CI 0.94-0.99). Insulin use did not reduce the risk of AMD.
Metformin use was associated with a reduced risk of AMD. Insulin did not show the same effect, suggesting that the protective mechanism of metformin may be separate from its anti-hyperglycemic effect. Metformin may contribute an anti-inflammatory effect that can protect against retinal cell death and angiogenesis, as has been demonstrated in murine models. The findings from this study set a foundation for future clinical trials and may allow clinicians to target the disease before the onset of irreversible retinal damage.
This is a 2020 ARVO Annual Meeting abstract.
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