The relationship between diabetic retinopathy, glycemic control, risk factor indicators and patient education

Background: Hyperglycemia, high blood pressure and hypercholesterolemia are risk factors for diabetic retinopathy and vision loss in diabetic patients. Objectives: To evaluate risk factors in patients treated for diabetic retinopathy in our hospital clinic and assess patients' awareness of the impact of glycemic control; and to compare the findings with those in patients followed in a community clinic. Methods: We performed a cross-sectional comparative study that included 178 consecutive patients with type 2 diabetes mellitus treated in the Retinal Vascular Service of Rabin Medical Center from 1 September to 31 December 2004, and 107 consecutive patients with type 2 diabetes mellitus examined in a community clinic during the same period. A questionnaire was completed; the main outcome measures were glycemic and risk factor control and their correlation with diabetic retinopathy and visual acuity. Results: Although only 43% of the patients had heard of HbA1c, 98% of them had undergone this analysis, with a mean level of 8.2% (SD 1.9) in the hospital patients and 7.7% (SD 1.6) in the community patients (P=0.01, t-test), HbA1c was lower in hospital patients who were aware of the test. Correlations were found for visual acuity, diabetic retinopathy and laser treatment with HbA1c ≤ 7%, cholesterol level < 200 mg/dl and blood pressure < 130/85 mmHg. Conclusions: Since our study and previous reports have shown that HbA1c level ≤ 7%, serum cholesterol level < 200 mg/dl and blood pressure < 130/85 mmHg are associated with better preservation of vision in patients with type 2 diabetes mellitus, we propose that the ophthalmologist has a role in educating patients about glucose, lipid and blood pressure control as part of the treatment of diabetic retinopathy.