Timing is Everything: Age of Onset Influences Long Term Retinopathy Risk in Type 2 Diabetes, Independent of Traditional Risk Factors.

Abstract

Objective. To test the hypothesis that age of type 2 diabetes onset influences inherent susceptibility to diabetic retinopathy, independent of disease duration and degree of hyperglycemia.

Research Design and Methods. Retinopathy data from 624 patients with type 2 diabetes duration of 20-30 years (Group A) were analysed by stratifying patients according to age of onset of diabetes and glycemic control. Retinopathy status was scored clinically as per a modified ETDRS severity scale. To obviate possible bias due to a higher attrition from co-morbidities against those with later onset diabetes and retinopathy, 852 patients with type 2 diabetes of shorter duration (10-12 yrs, Group B) were similarly studied.

Results. Prevalence and severity of retinopathy was significantly higher in the youngest onset Group A patients. When further stratified according to mean HbA1c, retinopathy risk remains increased in younger onset groups. The greatest impact was seen in those with a mean HbA1c >9% (OR for retinopathy: 16.6; 7.5; 2.7 for age of diagnosis <45 yrs, 45-55 yrs, >55yrs respectively, p=0.003). By logistic regression, earlier T2DM onset is associated with an increased retinopathy risk, independent of traditional risk factors (OR of retinopathy: 1.9; 1.1; 1; for age of onset <45, 45-55, >55 yrs, respectively). Group B patients behave similarly.

Conclusions. These data suggest an increased inherent susceptibility to diabetic retinopathy with earlier onset type 2 diabetes. This further supports the importance of delaying development of diabetes and also implies a need for more stringent metabolic targets for younger individuals.