The effect of SGLT-2 inhibitors on the retina in type 2 diabetes mellitus patients

ABSTRACT Objective: This study aimed to investigate the effects of SGLT-2 inhibitors on the retina in patients diagnosed with Type 2 Diabetes Mellitus (DM) by evaluating fundus examination and Optical Coherence Tomography Angiography (OCTA) measurements, particularly in the context of diabetic retinopathy. Materials and Methods: Conducted at Istanbul University-Cerrahpaşa Medical Faculty's Endocrinology and Metabolism Diseases Clinic, the study included 100 patients with Type 2 DM under regular follow-up. Patients were divided into two groups: those using SGLT-2 inhibitors and those not. Clinical data including sociodemographic information, body mass index, diabetes duration, HbA1c level, and lipid profile were recorded. For retinopathy evaluation, OCTA was used to measure parameters such as central macular thickness (CMT) and capillary density following fundus examination. Statistical analyses were performed using SPSS version 27, with p<0.05 considered statistically significant. Results: The study included 100 diabetic patients, with an average age of 58, of whom 59 were female and 41 were male. Among the 46 patients using SGLT-2 inhibitors, 28 were on Empagliflozin and 18 on Dapagliflozin. No significant difference was observed in CMT levels between the groups. In patients not using SGLT-2 inhibitors, measurements of deep capillary vessel density (DKVD) across the entire retina, parafovea, and perifovea, as well as superficial capillary vessel density (SKVD) in the perifovea, were significantly higher (p=0.016, p=0.015, p=0.021, and p=0.043, respectively). Additionally, inferior nasal, nasal inferior, and superior temporal radial peripapillary capillary (RPK) measurements were significantly elevated in the non-SGLT-2 inhibitor group (p=0.007, p=0.012, and p=0.026, respectively). Conclusion: This study did not demonstrate positive effects of SGLT-2 inhibitors on retinopathy progression in patients with Type 2 DM. This finding may be due to the longer disease duration and higher HbA1c levels in the SGLT-2 inhibitor group, which could present an elevated risk for diabetic complications. Prospective studies are recommended to explore this further. Keywords: Diabetic retinopathy, SGLT-2 inhibitor, Optical Coherence Tomography Angiography