Association Between Dipeptidyl Peptidase-4 Inhibitors and Diabetic Retinopathy in Korean Patients With Type 2 Diabetes Mellitus: Nationwide Population-Based Cohort Study

BACKGROUND Dipeptidyl peptidase-4 (DPP4) inhibitors are widely used to treat type 2 diabetes mellitus (T2DM). In a previous study, we demonstrated a plausible mechanism how DPP4 inhibitors may cause accumulation of stroma derived factor-1 (SDF1) in ischemic retina, leading to vascular permeability and diabetic retinopathy (DR). We sought to investigate the association of DPP4 inhibitors with DR in patients using the Korean National Health Insurance Service (NHIS) data. METHODS This was a retrospective, population-based cohort study using the Korean NHIS database. The Korean NHIS is a government-run, mandatory medical insurance service and keeps records of patient sociodemographic data, inpatient and outpatient medical services and prescriptions. The database consists of records from the entire Korean, totaling 51 million people, regardless of the medical institution from which they received service. RESULTS Among the total study population, 26.0% (152,149 of 585,191) received prescriptions of DPP4 inhibitors. The incidence of DR in the DPP4 inhibitor group was 55.03 per 1,000 person-years (PPY), compared to 50.17 PPY in the non-DPP4 group (P P