Low Hemoglobin Levels Increase Risk of Diabetic Retinopathy

The TriNetX network is a global health research database that can provide researchers access to electronic medical records from participating organizations. Using a large set of international data allows for investigations into how conditions, such as diabetes, can develop and alter the human body. In eye care, a recent study conducted in Taiwan collected information from this database in order to further the understanding of the risk of diabetic retinopathy (DR), a progressive cause of blindness in diabetic patients.Hyperglycemia is known as a major factor in the development of DR, but previous literature has suggested that low hemoglobin levels could impact its risk as well. To further investigate this proposition, researchers collected data on 57,764 patients in the TriNetX network from 2010 to 2022. Subjects were divided into two groups: low hemoglobin levels (8-12g/dL) and cohort (≥12g/dL) groups. Researchers analyzed their study’s population for the development of DR within six to 36 months of the index date (time in which hemoglobin levels were first tested) to produce a result. Their results were published recently in Eye. Low hemoglobin levels are associated with a higher risk of developing diabetic retinopathy; however, the presence of hypertension can further increase the risk. Regarding the risk of overall DR, the hazard ratio for patients with hypertension and low hemoglobin levels is 1.2, and the hazard ratio without hypertension is 1.6. Furthermore, patients with hypertension are not at a statistically significant risk for non-proliferative DR, yet patients without it are at risk. Click image to enlarge. The researchers calculated hazard ratios to determine the risk of DR. Overall, lower hemoglobin levels were associated with a significantly higher risk of DR compared to patient levels in the cohort (5.1% vs. 4.1%; HR: 1.3). When classified as proliferative and nonproliferative, results remained significantly higher (HR: 2 and 1.2). After compiling the data from subjects with any diabetic ophthalmic complication, low hemoglobin levels continued to remain a significantly higher risk factor (HR: 1.3). Additionally, mild reductions to hemoglobin levels—defined as 10 to 12 g/dL—were associated with a significantly higher risk for each subtype of DR and other diabetic-related ophthalmic complications. See this article for guidance on early identification of diabetic retinopathy. “The stronger association with proliferative diabetic retinopathy suggests that low hemoglobin levels may contribute to disease severity by promoting neovascularization, potentially via hypoxia-driven angiogenic pathways,” wrote the authors in their paper. “The finding that even mild reductions in hemoglobin significantly increased DR risk indicates that retinal tissue may be sensitive to even subtle changes in oxygen-carrying capacity.”Other results found were a stronger association to develop overall DR in patients with low hemoglobin levels and without hypertension (HR: 1.6), consistent findings regardless of HbA1c levels and a higher risk for overall DR discovered in males compared to females (HR: 1.5 vs. 1.3).“This relationship was observed even with mild reductions in hemoglobin and was modified by hypertension status and sex but remained consistent regardless of glycemic control,” concluded the authors. “Future research should focus on elucidating the precise mechanisms linking low hemoglobin levels to DR development and evaluating whether interventions to optimize hemoglobin levels can reduce the incidence or progression of DR in high-risk patients.”Click here for the journal source. Hung KC, Chang LC, Chang YJ, et al. Association between haemoglobin levels and the risk of diabetic retinopathy in adults with type 2 diabetes: a retrospective cohort study using the TriNetX network. Eye. September 6, 2025. [Epub ahead of print]. This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.