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

Hyperglycemia, high blood pressure and hypercholesterolemia are risk factors for diabetic retinopathy and vision loss in diabetic patients.

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.

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.

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 < or = 7%, cholesterol level < 200 mg/dl and blood pressure < 130/85 mmHg.

Since our study and previous reports have shown that HbA1c level < or = 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.