Natural Course of Congenital Hydronephrosis in Infants Aged 0-6 Months

Multicenter Prospective Cohort Study Protocol on the Natural Course of Congenital Hydronephrosis in Infants Aged 0-6 Months (3-Year Cycle)

This project aims to systematically delineate the natural progression of congenital hydronephrosis diagnosed within the critical window of 0-6 months through a prospective, multicenter, observational cohort study. The focus will be on analyzing the resolution rates, progression rates, and influencing factors of hydronephrosis of varying severities based on the UTD grading system.

Congenital hydronephrosis is one of the most common congenital urinary system abnormalities in children, with a high prenatal detection rate. However, its postnatal natural course is highly heterogeneous, leading to significant controversy in clinical management regarding follow-up intensity and intervention timing. Currently, there is a lack of prospective, large-sample, multicenter natural history data in China. By establishing a standardized follow-up system and collecting high-quality clinical and imaging data, this study aims to provide high-level evidence-based medical support for developing individualized and precise clinical management strategies, thereby reducing unnecessary interventions and delayed treatment. Consequently, conducting this multicenter study holds significant clinical and scientific value.

Study Overview

• Status: Not yet recruiting
• Conditions: Pediatric; Congenital Hydronephrosis; UTD Grading System; Natural Progression
• Intervention / Treatment: Other: No Intervention: Observational Cohort

• Study Type: Observational
• Enrollment (Estimated): 330

Contacts and Locations

• Study Contact: Name: Guangjie Chen; Phone Number: +86 13868175229; Email: dr.chenguangjie@zju.edu.cn

Study Locations

• China
  • Zhejiang
    • Hangzhou, Zhejiang, China, 310052
      • Children's hospital, Zhejiang Univeristy School of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Infants diagnosed with congenital hydronephrosis by abdominal ultrasound within 0-6 months after birth, meeting the UTD classification criteria (Grades I-III).

Description

Inclusion Criteria:

• Diagnostic Criteria: Congenital hydronephrosis is diagnosed by abdominal ultrasound examination and meets the UTD grading system criteria (Grades I-III). This is defined as an anterior-posterior renal pelvis diameter (APD) ≥4 mm during the fetal period or ≥7 mm after birth, or accompanied by calyceal dilation, renal parenchymal changes, and other manifestations.
• Informed Consent: The legal guardian voluntarily agrees to participate in the study and provides written informed consent.
• Follow-up Feasibility: The guardian commits to cooperating with the complete 3-year follow-up period, including attending regular examinations at the research center, and maintains stable contact information.

Exclusion Criteria:

• Presence of other severe congenital malformations that may affect follow-up or prognosis assessment, such as congenital heart disease, biliary atresia, spina bifida, etc.
• Secondary hydronephrosis caused by acquired factors (e.g., urinary system tumors, stones, trauma) or well-defined genetic metabolic diseases.
• Having received interventional treatments prior to enrollment, such as surgical procedures related to hydronephrosis (e.g., pyeloplasty) or pharmacological interventions (e.g., long-term use of diuretics).
• Severe underlying diseases that preclude tolerance for long-term follow-up, such as severe infections, respiratory failure, or renal failure (e.g., glomerular filtration rate < 30 ml/min/1.73m²).
• Inability of the legal guardian to cooperate due to mental illness, cognitive impairment, or refusal to comply with follow-up schedules and data collection requirements.

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
UTDⅠ	Other: No Intervention: Observational Cohort; No intervention
UTD II	Other: No Intervention: Observational Cohort; No intervention
UTD III	Other: No Intervention: Observational Cohort; No intervention

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hydronephrosis Resolution Rate	During the follow-up period (3 years), the child's hydronephrosis decreased from the UTD grade at enrollment to grade I or below, and this status persisted for ≥6 months.	During the follow-up period (3 years)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of Hydronephrosis Progression (UTD Classification)	Percentage of participants with an increase of ≥1 grade in the UTD classification compared to the baseline.	During the follow-up period (3 years)
Rate of Renal Parenchymal Thinning	Percentage of participants with a decrease of ≥2mm in renal parenchymal thickness from baseline measured by ultrasound.	During the follow-up period (3 years)
Incidence of Urinary Tract Infections (UTI)	The number of symptomatic UTI episodes per participant, characterized by a positive urine culture	During the follow-up period (3 years)
Change in Estimated Glomerular Filtration Rate (eGFR)	The mean change from baseline in eGFR levels to assess the trend of renal function over time.	During the follow-up period (3 years)
Change in Weight-for-age Z-score	The Z-scores are calculated based on the WHO Child Growth Standards to assess the child's weight development status.	During the follow-up period (3 years)
Change in Height-for-age Z-score	The Z-scores are calculated based on the WHO Child Growth Standards to assess the child's linear growth development status.	During the follow-up period (3 years)

Collaborators and Investigators

• Sponsor: The Children's Hospital of Zhejiang University School of Medicine

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2026
• Primary Completion (Estimated): March 1, 2028
• Study Completion (Estimated): November 30, 2028

Study Registration Dates

• First Submitted: December 10, 2025
• First Submitted That Met QC Criteria: January 30, 2026
• First Posted (Actual): February 3, 2026

Study Record Updates

• Last Update Posted (Actual): February 11, 2026
• Last Update Submitted That Met QC Criteria: February 8, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 2026-IRB-0038-P-01