Female Preponderance in the Discordant Association between Retinopathy and Nephropathy in Patients with Type 2 Diabetes Mellitus

Aim: To elucidate clinical features in patients with type 2 diabetes with advanced retinopathy but without nephropathy. Methods: This study examined 1324 patients (784 males and 540 females) with type 2 diabetes mellitus. Diabetic retinopathy was graded according to the International Clinical Classification of Diabetic Retinopathy as no diabetic retinopathy, mild or moderate non-proliferative diabetic retinopathy, severe non-proliferative diabetic retinopathy, and proliferative diabetic retinopathy. Diabetic nephropathy was classified into four stages of severity according to the Guideline Committee of the Japan Diabetes Society. Each patient was examined for retinopathy grade and nephropathy stage. Clinical features of patients with proliferative diabetic retinopathy were compared with regard to the four grades of diabetic nephropathy. Results: Fifty-two patients with type 2 diabetes (3.9% of the whole series of 1324 patients with type 2 diabetes and 25.7% of patients with proliferative diabetic retinopathy) had proliferative diabetic retinopathy without the presence of nephropathy. Multiple statistical analysis using a proportional odds model revealed that patients with proliferative diabetic retinopathy without nephropathy had a significantly lower systolic blood pressure (p < 0.001) than those who did and were preponderantly female (p < 0.05). Conclusions: A possible susceptibility of diabetic females to proliferative advanced retinopathy without nephropathy encourages further studies on the role of hormones and blood coagulation in the pathogensis of proliferative diabetic retinopathy.