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Metformin Use and Age-Related Macular Degeneration in Patients Without Diabetes

Sarthak Aggarwal, J. Moir, Max J. Hyman, Gabriel T Kaufmann, Andrea Flores, S. Hariprasad, D. Skondra

JAMA ophthalmology, 2023

231 participants · 29 citations

Abstract

Importance

Metformin use may protect against the development of age-related macular degeneration (AMD) based on results from observational studies. However, its potential effectiveness among patients without diabetes remains unclear.

Objective

To assess the association between metformin use and the development of AMD in patients without diabetes.

Design, Setting, and Participants

This case-control study used data from 2006 to 2017 in the Merative MarketScan Research Database, a nationwide insurance claims database that includes between 27 and 57 million patients in the US with primary or Medicare supplemental health insurance. Cases with AMD and controls without AMD aged 55 years or older were matched 1:1 by year, age, anemia, hypertension, region, and Charlson Comorbidity Index score. Then, cases and matched controls without a diagnosis of diabetes were selected. In subgroup analyses, cases with dry AMD and their matched controls were identified to explore the association between metformin use and AMD staging in patients without diabetes. Data were analyzed between March and September 2023.

Exposures

Exposure to metformin in the 2 years prior to the index date (ie, date of AMD diagnosis in cases and date of a randomly selected eye examination for controls) was assessed from the claims database and categorized into quartiles based on cumulative dose (1-270, 271-600, 601-1080, and >1080 g/2 y). Exposure to other antidiabetic medications was also noted.

Main Outcomes and…

How strong is the evidence?

Evidence Hub reads this as a case-control, done in people. Its evidence level is 4 of 5 (Low · observational). Observational designs can show an association but not prove cause. Reported size: 231 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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