Differences in pediatric continuous renal replacement therapy initiation and prescription practices between the jpCRRT registry and the WE-ROCK cohort.

INTRODUCTION: Pediatric continuous renal replacement therapy (CRRT) practice varies across regions, but contemporary registry-based comparisons are limited. We aimed to compare the patient characteristics, pre-CRRT status, and initial CRRT prescription patterns between the published Worldwide Exploration of Renal Replacement Outcomes Collaborative in Kidney Disease (WE-ROCK) cohort and a WE-ROCK-aligned cohort from the Japanese Pediatric Continuous Renal Replacement Therapy (jpCRRT) Registry. METHODS: This descriptive comparison used jpCRRT data collected from January 2023 to March 2026 from 13 participating PICUs in Japan and published aggregate data from WE-ROCK. To improve comparability, we excluded patients receiving maintenance dialysis before CRRT initiation, those treated with concomitant extracorporeal membrane oxygenation, and those receiving CRRT for metabolic or drug/toxin indications. The resulting WE-ROCK-aligned jpCRRT cohort comprised 70 patients. RESULTS: Compared with the WE-ROCK cohort, the jpCRRT cohort was younger and had lower body weight, with a shorter interval from intensive care unit admission to CRRT initiation. The pre-CRRT urine output and serum creatinine level were broadly similar between the cohorts. The initial CRRT practices differed substantially; continuous venovenous hemodialysis predominated in jpCRRT, whereas continuous venovenous hemodiafiltration predominated in WE-ROCK. Non-polysulfone membranes and nafamostat-based anticoagulants were common in jpCRRT, whereas polysulfone membranes and citrate anticoagulants were more frequently used in WE-ROCK. In contrast, vascular access distribution, blood flow rate, and prescribed CRRT dose were similar. Death before intensive care unit discharge occurred in 18.6% of the jpCRRT cohort and 35.8% of the WE-ROCK cohort. CONCLUSION: Contemporary pediatric CRRT practice differed between the published WE-ROCK cohort and the restricted jpCRRT cohort, particularly in terms of modality, filter type, and anticoagulation strategies. These findings suggest that pediatric CRRT practice is shaped by both regional implementation and patient case mix. Future international studies should use harmonized definitions and comparable outcome frameworks to better evaluate cross-regional differences in pediatric CRRT practice.