Diabetic retinopathy is a serious complication of diabetes that can lead to vision loss or blindness. It occurs when prolonged elevated blood sugar levels lead to changes in the smaller blood vessels in the eyes, specifically the retina. While there is no known cure for this condition, researchers have been exploring different ways to prevent or slow its progression. Overall, the goal of slowing or preventing diabetic retinopathy is to get your blood sugar levels under control. Of the many diabetic medications, GLP-1 agonists are among the most effective and are growing in popularity in part due to their favorable weight loss side effects.
GLP-1 agonists work by mimicking the effects of a hormone called glucagon-like peptide-1 (GLP-1), which is naturally produced by the body. GLP-1 helps regulate blood sugar levels and has been shown to have a protective effect on the eyes. In fact, oftentimes, patients and clinicians see a rapid decrease in HbA1c and blood sugar levels to a normal range. So with such a profound effect on blood sugar, this should be a good thing for diabetic retinopathy, right?
It turns out that it might not be the case. Many studies have shown that there is a conversely increased risk for diabetic retinopathy when rapidly correcting HbAlc levels. The idea that rapid blood sugar correction could lead to a transient increase in retinopathy came from a study published in 1985 (1). The study examined tight blood sugar control in patients with type 1 diabetes for a period of 1 year. The medication at that time was insulin injections. They found that retinopathy was seen in the patients with larger decreases in HbA1c. Though this was an older study, this inverse relationship is still seen in studies today.
Another study published in 2021 in Diabetes Care showed that HbA1c reductions when using GLP-1 agonists were associated with a significantly increased risk for retinopathy in people with diabetes (2). The study was a meta-analysis of six placebo-controlled trials of GLP-1 agonists on cardiovascular outcomes, this including retinopathy. However, these studies assessed risk in the short term (~3.4 years), so the long-term effects of GLP-1 agonists and retinopathy were not known.
So what does this mean? Should all diabetics avoid GLP-1 agonists? Though the risk does exist, GLP-1 agonists have been shown to have so many benefits and have changed patients' lives around the country. This means that it is extra important to inform your provider if you are at higher risk or have been diagnosed with diabetic retinopathy before you begin any GLP-1 agonist. However, if you are a non-diabetic, pre-diabetic, or diabetic and have been screened for retinopathy, then you do not have to worry.
If you were recently diagnosed with diabetes and are considering the use of GLP-1 agonists, your provider may request that you perform screening for retinopathy with an ophthalmologist. This is usually the standard recommendation for newly diagnosed diabetics regardless of starting GLP-1 agonists. If there are no signs of retinopathy and your risk is low, then you can decide with your provider whether a GLP-1 agonist is appropriate for you. If there are initial signs or concerns for retinopathy, then there are a plethora of other diabetic medications available. You can always discuss the risks and benefits of starting a GLP-1 medication with your provider.
If you would like to learn more about GLP-1 medications or want to see if you might be eligible for medication-assisted weight loss, check out Mochi Health, where board-certified obesity medicine physicians can offer expertise in this realm!
M. Angelyn Bethel, Rafael Diaz, Noelia Castellana, Indranil Bhattacharya, Hertzel C. Gerstein, Mark C. Lakshmanan; HbA1c Change and Diabetic Retinopathy During GLP-1 Receptor Agonist Cardiovascular Outcome Trials: A Meta-analysis and Meta-regression. Diabetes Care 1 January 2021; 44 (1): 290–296. https://doi.org/10.2337/dc20-1815
Dr. Constantine Joseph Pella, MD
Boston University Medical Center