Proliferative Diabetic Retinopathy in Young-Onset Type 1 Diabetes in Croatia: Risk Factors and a Predictive Economic Model for National Screening

<i>Background and Objectives:</i> To provide, for the first time, statistical data on risk factors for proliferative diabetic retinopathy (PDR) in young-onset type 1 diabetes (T1D) in Croatia, and to develop a predictive health economic model to evaluate the clinical and financial impact of implementing a national diabetic retinopathy (DR) screening. <i>Materials and Methods:</i> A cross-sectional study at University Hospital Split (June 2020-June 2022) analyzed 58 suitable T1D patients out of 562 screened. Patients were classified based on detailed fundus exams and photos into PDR and non-PDR groups. Clinical, demographic, and laboratory data were collected and analyzed using logistic regression. A health economic model was established to project the number of preventable PDR cases and the potential cost savings under various screening scenarios. <i>Results</i>: PDR was found in 47% of patients. Its presence was statistically significantly linked to longer diabetes duration, poor glycemic control, onset before 18 years of age, and irregular eye exams. Irregular ophthalmologic examinations increased the odds of PDR by nearly 30-fold. Health-economic modeling for 10,000 young-onset T1D patients showed that annual screening with 60% uptake could prevent about 1973 PDR cases and save €14.2 million annually. Screening remained cost-effective even with moderate uptake or less frequent intervals. <i>Conclusions</i>: Strict glycemic control and regular eye examinations are critical for preventing PDR in young T1D, and establishing a national screening program would be cost-effective, especially in resource-limited settings like Croatia, where providing appropriate, timely treatment may be challenging.