New Insights About Kidney Length in Pediatric ADPKD: Cross-Sectional Analysis of a Single-Center Cohort

Background: Kidney volume is a reliable biomarker of disease progression in adults with ADPKD, yet there are minimal data in pediatric ADPKD. We aimed to 1) establish a large pediatric ADPKD cohort and 2) compare kidney length with healthy controls, an important step in assessing kidney size as a potential marker for disease progression in children. Methods: We established a single-center retrospective cohort of subjects 0-18 years with ADPKD, based on ICD-9/10 codes, seen at the Children’s Hospital of Philadelphia between 2012-2024. Through Arcus, a CHOP-developed cloud-based computational platform, we used natural language processing (NLP) to initially build the cohort, with manual chart review for validation. For this cross-sectional analysis, kidney size was extracted from ultrasound (US) reports using NLP. Mean and median kidney length stratified by age was recorded and compared to healthy norms (Rosenbaum 1984) via 1-sample t-test. Genetic data was collected by chart review. Results: 225 patients were included in our cohort (52% female), with 87% concordance between NLP and chart review. One-third (72) of patients had genetic testing, with resolution in 70 (48 PKD1, 5 PKD2, 4 IFT140, 3 GANAB, 1 DNAJB11, 5 TSC2/PKD1, 4 Other). We excluded the 5 patients with TSC2/PKD1. 296 US reports from 220 subjects were analyzed, with the majority of US being obtained at initial presentation. ADPKD kidney length did not consistently differ from healthy controls before age 5 years. From 5-18 years, ADPKD kidney length was significantly increased compared to healthy norms (p<0.05) in all age groups except at 9-10 years (p=0.06) (Fig. 1). Conclusion: Our study is the largest single-center pediatric ADPKD cohort described to date. In this cross-sectional US-based analysis, we found no difference in kidney length in early childhood between ADPKD and healthy controls, but a significant divergence beginning at 5 years. These data have implications for using imaging-derived markers for risk prognostication in pediatric ADPKD. Further analysis in a longitudinal cohort, ideally informed by ADPKD genotype, will be required. Funding: Private Foundation Support