Abstract: FR-PO0956
Total vs. Normalized Excretion Rates for 24-Hour Urine Chemistries and Recurrent Stone Events in Adolescents: Results from the Prevention of Urinary Stones with Hydration (PUSH) Trial
Session Information
- Pediatric Nephrology: Genetic Diseases, Development, Neonatal Nephrology, Glomerular Diseases, and More
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pediatric Nephrology
- 1800 Pediatric Nephrology
Authors
- Tasian, Gregory Edward, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
- Maalouf, Naim M., The University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Best, Sara L., Laboratory Corporation of America, Itasca, Illinois, United States
- Harper, Jonathan D., University of Washington, Seattle, Washington, United States
- Desai, Alana C., University of Washington, Seattle, Washington, United States
- Reese, Peter P., Vanderbilt University, Nashville, Tennessee, United States
- Lai, Henry, University of Iowa Health Care, Iowa City, Iowa, United States
- Sivalingam, Sri, Cleveland Clinic, Cleveland, Ohio, United States
- Shah, Miloni, Duke University School of Medicine, Durham, North Carolina, United States
- Al-Khalidi, Hussein, Duke University School of Medicine, Durham, North Carolina, United States
- Kirkali, Ziya, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, United States
- Scales, Charles D., Duke University School of Medicine, Durham, North Carolina, United States
Group or Team Name
- Urinary Stone Disease Research Network
Background
24-hour urine chemistries for adolescents with urinary stones are interpreted using either total excretion rates (adult paradigm) or excretion rates normalized to body size (pediatric paradigm), but the clinical applicability of these different rates are uncertain.
Methods
We performed a secondary analysis of adolescents aged 12–17 years in the Prevention of Urinary Stones with Hydration randomized trial. Baseline 24-hour urine chemistries were evaluated as total excretion rates and as excretion rates normalized to body weight, body surface area, or creatinine, as appropriate. Each parameter was classified as in- versus out-of-range using Litholink reference ranges to assess concordance/discordance between approaches. We then fit adjusted logistic regression models to estimate associations with first symptomatic stone event (passage or surgery) and compared model fit and discrimination (AUC) for total versus normalized specifications. Sensitivity analyses restricted to ages 13–16 years assessed discrimination during a period of rapid growth.
Results
Among 197 participants (median age 15.1 years; 63.5% female), 36 (18.3%) experienced a symptomatic stone event over 2-years of follow-up. Total versus normalized excretion rates were concordant for 85% and discordant for 15%, with the highest discordance of 48% for hypocitraturia. Discrimination was modest and similar for total rates (AUC 0.63; 95% CI, 0.53–0.74) versus normalized rates (AUC 0.64; 95% CI, 0.52–0.75), with small differences in fit indices and wide confidence intervals for most effects. In age-restricted analysis, the normalized model showed higher discrimination than the total excretion model (AUC 0.81; 95% CI, 0.71–0.91) vs 0.68 (95% CI, 0.55–0.82), respectively.
Conclusion
In adolescent stone-forming patients, classification of within normal reference ranges for total and normalized excretion rates are discordant for a meaningful minority. Neither approach robustly predicts symptomatic recurrence, though normalized rates may perform better in early to mid-adolescence, supporting external validation to develop outcome-based, age-specific reference standards.
Funding
- NIDDK Support