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Metformin and risk of age-related macular degeneration in individuals with type 2 diabetes: a retrospective cohort study

K. Gokhale, N. Adderley, A. Subramanian, Wen Hwa Lee, Diana Han, Jesse Coker, T. Braithwaite, A. Denniston et al.

British Journal of Ophthalmology, 2022

173 participants · 22 citations

Abstract

Background Age-related macular degeneration (AMD) in its late stages is a leading cause of sight loss in developed countries. Some previous studies have suggested that metformin may be associated with a reduced risk of developing AMD, but the evidence is inconclusive. Aims To explore the relationship between metformin use and development of AMD among patients with type 2 diabetes in the UK. Methods A large, population-based retrospective open cohort study with a time-dependent exposure design was carried out using IQVIA Medical Research Data, 1995–2019. Patients aged ≥40 with diagnosed type 2 diabetes were included. The exposed group was those prescribed metformin (with or without any other antidiabetic medications); the comparator (unexposed) group was those prescribed other antidiabetic medications only. The exposure status was treated as time varying, collected at 3-monthly time intervals. Extended Cox proportional hazards regression was used to calculate the adjusted HRs for development of the outcome, newly diagnosed AMD. Results A total of 173 689 patients, 57% men, mean (SD) age 62.8 (11.6) years, with incident type 2 diabetes and a record of one or more antidiabetic medications were included in the study. Median follow-up was 4.8 (IQR 2.3–8.3, range 0.5–23.8) years. 3111 (1.8%) patients developed AMD. The adjusted HR for diagnosis of AMD was 1.02 (95% CI 0.92 to 1.12) in patients prescribed metformin (with or without other antidiabetic medications) compared with…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 173 participants or records.

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