Metabolic control of diabetes is associated with an improved response of diabetic retinopathy to panretinal photocoagulation.

OBJECTIVE To study the influence of glycemic control and the presence of microalbuminuria on the initial response to panretinal photocoagulation (PRP) in patients with a high-risk proliferative diabetic retinopathy (PDR). RESEARCH DESIGN AND METHODS This was a prospective cohort study with a two-by-two factorial design. We used full-scattered PRP to treat 115 eyes of type 2 diabetic patients who have high-risk PDR. HbA1c (A1C) and albumin levels in 24-h urine were constantly monitored during the pre-enrollment, treatment, and posttreatment periods. At a follow-up visit 12 weeks after the last PRP session, the fundus was examined for characteristics of regression from high-risk PDR and the response to PRP was determined to be successful or unsuccessful. The eyes were categorized into four groups based on average A1C levels and the presence or absence of microalbuminuria. The data were analyzed using a logistic regression model. Our statistical analysis determined the probability of achieving a satisfactory response to PRP in association with A1C levels and the presence or absence of microalbuminuria. RESULTS Of the 115 eyes examined, 65 (56.5%) had a successful initial response to PRP and 50 (43.5%) did not. The probability of a satisfactory response to PRP was related to A1C levels (P < 0.05) but not to microalbuminuria and its interaction with hemoglobin glycosylation (P > or = 0.05). CONCLUSIONS Low levels of hemoglobin glycosylation (A1C <8%) during the pretreatment, treatment, and posttreatment periods are associated with a regression of proliferative diabetic retinopathy after PRP.