Objective: To examine longitudinal data about depression in relationship to glycemic control and as a risk factor for diabetic retinopathy (DR). Depression is a common psychiatric disorder among diabetic persons and has been shown in cross-sectional studies to be associated with the vascular complications of diabetes.
Methods: A total of 483 African-American patients with Type 1 diabetes had a baseline examination and 6-year follow-up examination. Evaluations at both visits included administering the Beck Depression Inventory (BDI), a detailed ophthalmologic examination, retinal photographs, and measurement of glycosylated hemoglobin as an index of glycemic control. Six-year progression of DR between baseline and follow-up visits was evaluated from the change in retinopathy severity using the Early Treatment of Diabetic Retinopathy Study grading scale.
Results: Patients with high BDI scores at both baseline and 6-year follow-up visits had significantly higher baseline glycosylated hemoglobin values (p = .01), and were more likely to show progression of DR (odds ratio (OR) = 2.44; 95% confidence interval (CI): 1.01-5.88; p = .049) and progression to proliferative diabetic retinopathy (PDR) (OR = 3.19; 95% CI: 1.30-7.87; p = .01) than patients with low BDI scores at both visits. This was independent of baseline medical risk factors for DR.
Conclusion: Six-year longitudinal data indicate that depression is significantly associated with both poor glycemic control and higher 6-year progression to PDR in African-Americans with Type 1 diabetes.