Tehran University of Medical Sciences Journal of Biostatistics and Epidemiology 2383-4196 4 2 2018 10 31 47 51 EN Maryam Nazemipour Department of Epidemiology and Biostatistics, School of Public Health, International Campus, Tehran University of Medical Sciences, Tehran, Iran. Abdol-Mohammad Kajbafzadeh Pediatric Urology Research Center, Department of Pediatric Urology, Children’s Hospital Medical Center, Tehran University of Medical Sciences, Tehran, Iran. Kazem Mohammad Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. Mahmood Mahmoudi Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. 2018 07 31 Background & Aim: Prediction of time to reflux can aid healthcare providers and preparation programs. We constructed a risk prediction instrument for occurrence reflux in children with antenatal hydronephrosis. Methods & Materials: Demographic and clinical information was collected retrospectively in children with the antenatal hydronephrosis and mostly with reflux, followed at least 5 years. Results: Accelerated failure time model of data from 333 children was developed to assess the risk of time to reflux. Likelihood ratio tests of statistical significant were used to identify best fitting predictive function. Variables “gender”, “Sr”, and “severity of ANH (in severe level)” were highly significant (p<0.05) in multivariate model, adjusting for some traditional risk factors. Conclusion: This proposed risk probability model allows prediction of time to reflux for children with antenatal hydronephrosis to better inform parents from possible time of occurrence reflux and treatment strategies. https://jbe.tums.ac.ir/index.php/jbe/article/view/207 https://jbe.tums.ac.ir/index.php/jbe/article/download/207/158