Retinopathy during the First 5 Years of Type 1 Diabetes and Subsequent Risk of Advanced Retinopathy

Objectives: To determine whether individuals with type 1 diabetes (T1D) who develop any retinopathy at any time prior to five years of diabetes duration have an increased subsequent risk for further progression of retinopathy or onset of proliferative diabetic retinopathy (PDR), clinically significant macular edema (CSME), diabetes-related retinal photocoagulation or anti-VEGF injections. Additionally, to determine the influence of HbA1c and other risk factors in these individuals.

Methods: Diabetic retinopathy (DR) was assessed longitudinally using standardized stereoscopic seven-field fundus photography at time intervals of six months to four years. Early onset DR (EDR) was defined as onset prior to 5 years of T1D duration. Cox models assessed the associations of EDR with subsequent risk of outcomes.

Results: In unadjusted models, individuals with EDR (n=484) had an increased subsequent risk of PDR (hazard ratio HR=1.51, 95%CI [1.12,2.02], P=0.006), CSME (HR=1.44, [1.10,1.88], P=0.008) and diabetes-related retinal photocoagulation (HR=1.48, [1.12,1.96], P=0.006) compared to individuals without EDR (n=369). These associations remained significant adjusted for HbA1c, but only the association with PDR remained significant after adjustment for age, duration of T1D, HbA1c, sex, systolic/diastolic blood pressure, pulse, use of ACE inhibitors, albumin excretion rate, and eGFR (HR=1.47, [1.04,2.06], P=0.028).

Conclusions: These data suggest that individuals with any sign of retinopathy within the first 5 years of T1D onset may be at higher risk of long-term development of advanced DR, especially PDR. Identification of early onset DR may influence prognosis and help guide therapeutic management to reduce the risk of future visual loss in these individuals.