Prevalence and Characteristics of Patients with Cystic Fibrosis-Related Diabetes in Croatia

This study investigated the prevalence of cystic fibrosis-related diabetes (CFRD) in the Croatian cystic fibrosis (CF) population, the age at diagnosis, insulin requirements, and the relationship between age at diagnosis and other clinical parameters. Medical records from 152 patients with genetically and laboratory-confirmed CF were reviewed through to 2025. The American Diabetes Association criteria were used to diagnose CFRD. Anthropometric and clinical data were collected from the latest medical records. A total of 17 out of 152 patients had CFRD, with a prevalence of 4.8% in the paediatric population (4/84) and 19.1% in adults (13/68). The median age of CFRD diagnosis was 14 years (range 9-22 years, SD = 3.95). Thirteen patients used insulin: one used bolus only, seven used basal-bolus multiple daily injections, and five used insulin pumps. The average total daily insulin (TDI) per kilogram (kg) body weight was 0.447 U/kg (SD = 0.429). The age at CFRD diagnosis was positively correlated with the body mass index (BMI) (<i>p</i> = 0.029). Patients requiring insulin by age 15 had higher TDI and were more likely to have CF liver disease (<i>p</i> = 0.027, <i>p</i> = 0.037, respectively). The prevalence of CFRD and age at diagnosis aligned with previous studies. Patients diagnosed at a younger age and requiring insulin earlier had lower BMIs, likely due to a faster decline in beta cell function and earlier onset of insulinopenia.