Effect of basal insulin supplement therapy on diabetic retinopathy in short‐duration type 2 diabetes: A one‐year randomized parallel‐group trial

BACKGROUND: In this study, we compared the effect on diabetic retinopathy (DR) between oral antidiabetic drugs (OADs) alone and in combination with basal insulin‐supported OADs therapy (BOT). [Correction added on 11 November 2019, after first online publication: In Abstract under Background section, “DR” has been corrected into “diabetic retinopathy (DR)”.] METHODS: Between January 2015 and January 2018, this study enrolled 290 patients (age 18‐65 years) with diabetes duration between 0 and 5 years. Patients were randomly assigned to receive OADs or BOT after 14 days intensive insulin treatment. Examinations were performed at the beginning and end of the study. RESULTS: Fewer patients developed DR in the BOT than OADs group (8 [6.06%] vs 12 [8.3%], respectively), and all cases of DR were non‐proliferative. Blood glucose concentrations were higher in the BOT than OADs group at the 3rd month, but lower in the former at the 6th and 12th month. The rate of reaching target HbA1c ≤7% was lower in the BOT than OADs group at the 3rd month (63.6% vs 72.2%, respectively), similar between the two groups at the 6th month (60.6% vs 66.6%, respectively) and higher in the BOT group at the 12th month (75.0% vs 61.1%, respectively). The SD of fasting blood glucose (FBG), coefficient of variation of FBG, SD of blood glucose (SDBG), and mean amplitude of glycemic excursions were lower in the BOT than OADs group. Changes in the levels of three cytokines (interleukin [IL]‐1β, IL‐6, and IL‐17α) were significantly less in the BOT than OADs group. CONCLUSIONS: Twelve months of BOT decreased the incidence of DR in short‐duration type 2 diabetes by reducing glycemia more effectively, stably, and completely than OADs alone.