Association of Types of Diabetic Macular Edema with Different Anti-Diabetic Therapies

Objective: To evaluate and assess the association of diabetic macular edema with different anti-diabetic therapy regimens. Material and Methods: We recruited 340 patients with prediagnosed Type 2 diabetes mellitus attending the ophthalmology and medicine outpatient department. Patients were older than 30 years with Type 2 diabetes mellitus and on a specific anti-diabetic regimen (monotherapy/combination therapy) for ≥6 months, and who underwent macular edema assessment by using spectral domain optical coherence tomography. The patterns of macular edema per retinal morphology were grouped as diffuse retinal thickening, cystoid macular edema, and serous retinal detachment. Results: No significant association was found between edema pattern and dual therapy regimen (metformin+1 other oral hypoglycemic agent) (p=0.685) in the 680 eyes of the 340 patients. In patients on all the other triple therapy regimens (metformin+2 other oral hypoglycemic agents), diffuse retinal thickening was the most common type, except in patients on thiazolidinediones and insulin in conjunction with metformin in which cystoid macular edema was the most common. However, the difference between different triple therapy regimens was statistically significant (p=0.053). Conclusion: The most common form of macular edema was diffuse retinal thickening irrespective of the type and regimen of anti-diabetic therapy. Increased incidence of cystoid macular edema was observed in patients on triple therapy, including insulin. Because of the difference in the patterns, it is imperative to evaluate patients for different types of edema due to ongoing anti-diabetic treatment.