Two decades of kidney stone interventional trials on clinicaltrials.gov: a registry-based landscape analysis of design, endpoints, and dissemination.

Abstract

Despite major advances in kidney-stone management, the clinical-trial landscape in nephrolithiasis has not been systematically characterized. We performed a 20-year registry-based landscape analysis of interventional kidney-stone trials, focusing on trial design, primary endpoint selection, infrastructure, and dissemination. ClinicalTrials.gov was searched for interventional kidney-stone trials with primary completion dates between June 23, 2005 and June 23, 2025. Trials were categorized by lead sponsor type, study design, center status, intervention category, and primary endpoint domain. Temporal trends in primary endpoint selection were assessed by registration era. Publication status, ClinicalTrials.gov results posting, and intervals from registration to results posting, study start to publication, and primary completion to publication were evaluated among completed trials. A total of 57 trials met inclusion criteria. Most had an academic lead sponsor (49/57, 86.0%), were randomized (43/57, 75.4%), completed (51/57, 89.5%), single-center (38/57, 66.7%) and US-based (53/57, 93.0%). Medical/pharmacologic interventions were most common (33/57, 57.9%), followed by procedural/device-based (17/57, 29.8%) and preventive/behavioral/other interventions (7/57, 12.3%). Primary endpoints most often focused on stone-related efficacy (25/57, 43.9%), followed by pain/quality-of-life/patient-reported outcomes (16/57, 28.1%), complication/safety outcomes (9/57, 15.8%), and operational/resource-use outcomes (7/57, 12.3%). By registration era, stone-related efficacy endpoints declined from 69% in 2005-2015 to 23% in 2016-2025, while pain/quality-of-life endpoints increased from 15% to 39%. Female representation averaged 43.3%, with a median of 47.9%. In the 2-year publication-mature cohort, 39 of 49 trials (79.6%) were published; among all 51 completed trials, 41 (80.4%) were published. Median registration-to-results and study-start-to-publication intervals were 45 and 48 months, respectively, while the median primary-completion-to-publication interval was 15 months. Within ClinicalTrials.gov, interventional kidney-stone trials remain largely academic and single-center, reflecting active but fragmented research infrastructure within this registry. Although stone-related efficacy remains the dominant primary endpoint, recent trials show increasing emphasis on patient-centered primary outcomes. A persistent unpublished fraction and publication commonly occurring more than one year after primary completion highlight the need for multicenter collaboration, standardized patient-centered endpoints, and timely dissemination.