Is Metformin related to Macular Degeneration in Diabetes patients?

There is no indication that metformin is linked to an increased risk of age-related macular degeneration (AMD) among type 2 diabetes patients in primary care, reports an article published in British Journal of Ophthalmology on 3rd February, 2022.

In affluent countries, late-stage age-related macular degeneration is the major cause of vision loss. Metformin has been linked to a lower incidence of AMD in several earlier studies, however the evidence is ambiguous. As a result, Krishna M Gokhale and colleagues undertook this research to investigate the link between metformin use and the development of AMD in type 2 diabetes patients in the United Kingdom.

IQVIA Medical Research Data, 1995–2019, was used to conduct a large, population-based retrospective open cohort study using a time-dependent exposure design. For this, patients under the age of 40 who had been diagnosed with type 2 diabetes were included in the study. Those provided metformin (with or without any other antidiabetic medications) were in the exposed group; those prescribed just other antidiabetic medications were in the comparative (unexposed) group. The exposure status was recorded at 3-monthly intervals and was handled as time changing. The adjusted HRs for the development of the outcome, newly diagnosed AMD, were calculated using extended Cox proportional hazards regression.

The results of this study stated as follow:

1. 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 drugs were included in the study.

2. The average length of follow-up was 4.8 years (IQR 2.3–8.3, range 0.5–23.8). 3111 (1.8 percent ) individuals acquire AMD.

3. In individuals taking metformin (with or without additional antidiabetic drugs), the adjusted HR for diagnosis of AMD was 1.02 (95% CI 0.92 to 1.12) compared to those prescribed any other antidiabetic medication exclusively.

In conclusion, from the findings of this study there is no such evident relationship coming out between use of metformin and its implications with AMD in patients with type-2 DM.

Reference:

Gokhale KM, Adderley NJ, Subramanian A, Lee WH, Han D, Coker J, Braithwaite T, Denniston AK, Keane PA, Nirantharakumar K. Metformin and risk of age-related macular degeneration in individuals with type 2 diabetes: a retrospective cohort study. Br J Ophthalmol. 2022 Feb 3:bjophthalmol-2021-319641. doi:10.1136/bjophthalmol-2021-319641.