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Predicting Time to Reflux of Children With Antenatal Hydronephrosis: A Competing Risks Approach
Maryam Nazemipour1, Abdol-Mohammad Kajbafzadeh2, Kazem Mohammad3
1Department of Epidemiology and Biostatistics, School of Public Health, International Campus, Tehran University of Medical Sciences, Tehran, Iran.
Insights
This study introduces a trivariate Weibull survival model to analyze reflux types in children with antenatal hydronephrosis, offering a more appropriate method than standard models for competing risks analysis.
Area of Science:
- Pediatric Urology
- Survival Analysis
- Medical Statistics
Background:
- Antenatal hydronephrosis (ANH) is a common condition in newborns.
- Urinary tract infections and reflux are significant complications of ANH.
- Accurate prediction of reflux occurrence is crucial for timely intervention.
Purpose of the Study:
- To describe methodological aspects of a trivariate Weibull survival model.
- To apply this model to predict the time to different types of reflux (left, right, bilateral) in children with ANH.
- To evaluate the impact of demographic and clinical factors on reflux development.
Main Methods:
- Utilized data from 333 children diagnosed with ANH.
- Employed a trivariate Weibull survival model incorporating the competing risks concept.
- Assessed the independence assumption between different reflux types.
Main Results:
- Identified significant predictors for left, right, and bilateral reflux.
- Demonstrated that 80.5% of infants were male.
- Highlighted the inadequacy of Kaplan-Meier and standard Cox models for competing risks.
Conclusions:
- The trivariate Weibull model with competing risks is superior for analyzing reflux in ANH patients.
- This model accurately calculates hazard rates for different reflux types and covariates.
- Findings provide valuable insights for managing pediatric urinary tract issues.
Abstract:
The aim of this study was describing methodological aspects and applying a trivariate Weibull survival model using the competing risks concept to predict time to occurrence different types of reflux (unilateral (left, right) or bilateral) in children with antenatal hydronephrosis. Data from 333 children in Pediatric Urology Research Center of Children's Hospital Medical Center, affiliated with Tehran University of Medical Sciences was used. The effect of some demographic and clinical factors on child's reflux was studied. The assumption of independent between times of different types of reflux was evaluated. Of infants 80.5% were boy. The percentage of children experienced right, left and bilateral reflux or have been censored are 15.3%, 14.1%, 60.4% and 10.2% respectively. For the time of left reflux, variables, Week of diagnosis ANH, UC, UA, HUN, HN, APD_Right, Direction of ANH, CA19-9 baby, Urethra were significant. For the time of right reflux, variables, constipation, UC, UA, HUN, APD_Right, Direction and Severity of ANH, Bladder, and finally for the time of bilateral reflux, variables, Week of diagnosis ANH, Gender, UA, HUN, HN, APD_Left, Urethra, and Bladder were significant P<0.05. In the presence of competing risks, it is inappropriate to use the Kaplan-Meier method and standard Cox model which do not take competing risks into account. Trivariate Weibull survival model using competing risks not only is able to calculate the hazard rate of variables with different type of events but also it will be able to compare the hazard rate within the same type of event with different covariates.
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