Characterizing children with chronic kidney disease and severe proteinuria in the United States: a retrospective analysis using electronic health records

BACKGROUND: In recent years, real-world data have been increasingly used to enrich data from interventional studies on treatment effectiveness. To explore the viability of hybrid study designs in pediatric chronic kidney disease (CKD), we assessed the feasibility of identifying a real-world cohort of children with CKD and severely increased proteinuria who satisfied adapted eligibility criteria from the FIONA trial. METHODS: We used data from the Optum® de-identified Electronic Health Record dataset (Optum® EHR) to identify and characterize children with CKD and severely increased proteinuria in records from January 2013 to December 2022. Patients were identified based on two sets of estimated glomerular filtration rate (eGFR)/serum creatinine and urine protein-to-creatinine ratio (UPCR) measures within a 90- to 365-day period (final date = index). Patients were required to satisfy adapted eligibility criteria from the FIONA trial and have a baseline prescription for angiotensin-converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARBs). Patients were stratified by eGFR and UPCR. Patient characteristics, comorbidities, and medications were descriptively reported. RESULTS: and 69.0% had UPCR > 1 g/g. The patient distribution by CKD stage was: G1, 50.9%; G2, 29.9%; G3-4, 19.2%. Among 397 patients who were excluded given no baseline ACEi/ARB use, > 20% initiated ACEi/ARBs within 6 months following index. CONCLUSIONS: Our study demonstrated the feasibility of identifying a real-world pediatric cohort with CKD and severely increased proteinuria using adapted criteria from the FIONA trial. Findings from this study highlight factors that should be considered in the design of future hybrid studies evaluating treatment effectiveness using data from both trials and the real world.