A study published in JAMA Ophthalmology found that metformin use and lifestyle changes were not associated with the prevalence of age-related macular degeneration (AMD). Neither was the duration of metformin use found to be associated with AMD.
AMD is the most common age-related eye condition in the United States and is a leading cause of blindness. The neovascular stage remains the only stage of AMD that can be treated with therapies. This current study examined the association between preventing or delaying the development of AMD and metformin use and lifestyle changes initiated to prevent diabetes.
This study used the Diabetes Prevention Program (DPP) for its data, which was a multicenter controlled clinical trial that enrolled patients at risk of being diagnosed with diabetes. The study separated the participants into 3 groups: a lifestyle intervention group focused on achieving physical activity of at least 150 minutes in a week; a metformin group receiving 850 mg twice daily with a standard diet and exercise routine; and a double-blind placebo group with standard diet and exercise.
The Diabetes Prevention Program Outcome Study, which was a follow-up study to assess the association of DPP interventions with outcomes, used fundus photography and optical coherence tomography (SD-OCT) imaging to assess the association between AMD and metformin. The images were taken in 2018 in the 16th year of follow-up. AMD was determined using these photographs.
There were 2051 participants who had attended the 16-year follow-up. Participants had a mean (SD) age of 49 (9) years and 71% were male. There were 1,587 participants who underwent retinal imaging for this study, of whom 513 (32.3%) were in the lifestyle group, 546 (34.4%) were in the metformin group, and 528 (33.2%) were in the placebo group. No significant differences in age, sex, race and ethnicity, smoking status, or body mass index were found in these groups.
A higher proportion of patients in the placebo group had type 2 diabetes. Metformin was used for a median (IQR) of 0 (0-7) years in the lifestyle group, 18.5 (9.5-20 .3) years in the metformin group and 1.5 (0-8.5) years in the placebo group.
AMD was found in 479 participants (30%), with early-stage AMD accounting for 14.4%, intermediate AMD accounting for 13.7%, and advanced AMD accounting for 2%. AMD severity agreed between color photography and SD-OCT in 92.9% of all eyes.
The prevalence of AMD was found to be 29.6% in the lifestyle group, 30.2% in the metformin group, and 30.7% in the placebo group. Age was significantly higher in the AMD group compared to those without AMD (mean [SD] age, 51.4 [9.6] against 48 [8.6] years). Smoking was associated with the prevalence of AMD (odds ratio [OR], 1.3; 95% CI, 1.1-1.6).
The prevalence of AMD was 28.8% in patients who used metformin regardless of duration and was 33.5% in patients who had never used metformin. No association was found between metformin use and AMD. The mean number of years metformin was used was not significantly different in patients with and without AMD. The OR for the likelihood of AMD with the number of years metformin use was 1.0 (95% CI, 0.9-1.2).
There were some limitations in this study. The relationship between metformin and the incidence or progression of AMD could not be assessed in this cross-sectional study. The use of metformin outside the study could have affected the assessment of the relationship. The cohort was generally healthy. Generalizability was limited as it only included adults at increased risk of being diagnosed with diabetes.
The investigators concluded that no relationship could be found between the prevalence of AMD and metformin use.
Reference
Domalpally A, Whittier SA, Pan Q, et al. Association of metformin with the development of age-related macular degeneration. JAMA Ophthalmol. Published online December 22, 2022. doi:10.1001/jamaophthalmol.2022.5567
Source: news.google.com