Estimating the Lag Between Onset and Diagnosis of Diabetes from the Prevalence of Diabetic Retinopathy Among Indian Population

Background & Objectives: Type 2 Diabetes Mellitus (T2DM) is often characterized by an asymptomatic phase of around 4-7 years between the onset of diabetes and its clinical diagnosis. Diabetic retinopathy is the one to be observed as an early sign of microvascular complications. The objective of the present study was investigate the time lag between the onset of hyperglycemia and clinical diagnosis of T2DM. Methods: The present cross-sectional study was done at an outpatient setting of an endocrinology clinic. According to inclusion criteria, consecutive patients subjects of either sex with T2DM either newly diagnosed at the time of first encounter with study investigator or previously diagnosed with any duration of T2DM were eligible to be recruited in the present study. A weighted linear regression analysis was performed to estimate the prevalence of retinopathy at each time point. The period at which the prevalence of retinopathy was zero is back extrapolated from the graph to get onset of diagnosis. Results and Interpretations: A total of 1407 patients with T2DM are included in present analysis. 52% (n = 725) were females and mean (SD) age was 54.3 (10.1) years. The prevalence of diabetic retinopathy was found to be 13.7% (n = 194) at the time of clinical diagnoses. Prevalence of retinopathy increased linearly with duration of T2DM. Estimated the actual onset of time of diabetes was found to be 11.4 (95% CI, 9.5-15) years before the patients were clinically diagnosed with T2DM. Conclusions: High diagnostic lag was observed in present study. It indicates that there is a need for continues education, counseling of high risk population on diabetes mellitus and its complications to increase awareness of diabetes and reduction of diagnostic lag