Systemic Predictors of Diabetic Retinopathy and Diabetic Macular Edema in an Adult Veteran Population

Purpose: To investigate the influence of systemic and serum measures and hypoglycemic medications on the initial presentation and ongoing development of diabetic retinopathy (DR) and diabetic macular edema (DME).

Design: Using Veterans Affairs electronic health records, we identified patients with a diabetes mellitus diagnosis and at least one eye examination between 1997 and 2010. After adjusting for sociodemographic factors, we used multivariable Cox regression models to evaluate the association of hemoglobin A1c (HbA1c) levels, blood pressure, albuminuria, blood urea nitrogen (BUN), and prescribed medications with the subsequent diagnosis of 1) any diabetic eye disease (defined for this analysis as DR and/or DME, 2) diabetic retinopathy, and 3) diabetic macular edema.

Results: Of 4089 diabetic Veteran patients, 821 (20%) were subsequently diagnosed with diabetic retinopathy and 88 (2%) had macular edema. Patients were more likely to receive a diabetic retinopathy diagnosis if they presented with HbA1c > 8.5 (HR=2.66, 95% CI 1.88-3.77, p<0.01), systolic blood pressure > 140 mmHg (HR=1.45, 95% CI 1.26-1.66, p<0.01), blood urea nitrogen (BUN) > 35 mg/dL (HR=2.17, 95% CI 1.60-2.93, p<0.01), and/or used insulin (HR=2.04, 95% CI 1.74-2.40, p<0.01). Patients were more likely to be diagnosed with diabetic macular edema if they had systolic blood pressure > 140 mmHg (HR=2.00, CI 1.29-3.08, p<0.01) and/or used insulin (HR=2.48, CI 1.53-4.03, p<0.01).

Conclusion: Markers of systemic health may be useful predictors for incident diabetic retinopathy or diabetic macular edema, evaluated collectively in Veteran patients. Higher HbA1c levels, systolic blood pressure, BUN levels, and insulin use (suggestive of more severe and/or long-standing diabetes) appear to be highly associated with the development of diabetic eye disease, and, in particular, diabetic retinopathy.