Impact of Insulin Treatment in Diabetic Macular Edema Therapy in Type 2 Diabetes

Objective: To evaluate the impact of insulin therapy on the outcomes of diabetic macular edema (DME) treatment with vascular endothelial growth factor (VEGF) inhibitors in people with type 2 diabetes. Methods: A retrospective consecutive case series of 95 patients with type 2 diabetes and DME who were treated with anti-VEGF therapy. We examined 2 cohorts: patients taking only oral antidiabetic agents and patients on insulin therapy. The main outcome measures were change in visual acuity and change in central subfield macular thickness measured by spectral-domain optical coherence tomography. The additional variables analyzed included glycated hemoglobin (A1C), creatinine, blood pressure and body mass index and their correlations with clinical findings. Results: Both groups had a statistically significant improvement in visual acuity (oral antidiabetic agents group: 20/61 to 20/49, p=0.003; insulin therapy group: 20/76 to 20/56, p=0.005). There was no difference between groups at initial or 12-month examination (p=0.239 and p=0.489, respectively). From an anatomic standpoint, central subfield macular thickness also improved significantly in both groups: from 454.7 mu m to 354.9 mu m (p<0.001) in the oral antidiabetic agents group and from 471.5 mu m to 368.4 mu m (p<0.001) in the insulin therapy group. Again, there was no significant difference between groups at initial or 12-month follow-up examinations (p=0.586 and p=0.591, respectively). Mean A1C levels remained relatively stable during the follow up in both groups. Conclusion: Anti-VEGF therapy is a useful treatment for DME. This study Suggests that chronic insulin therapy, compared with oral antidiabetic agents, does not modify the anatomic or functional effectiveness of DME treatment. (C) 2015 Canadian Diabetes Association