Methods of competing risks analysis of time to occurrence of reflux among children with antenatal hydronephrosis

Background & Aim: We aimed to describe a standard survival analysis, so that we can analyze some factors related to the time of occurrence of different types of reflux (unilateral-left, unilateralright, and bilateral) in children with antenatal hydronephrosis (ANH) and to provide an approach taking competing risks into account. Methods & Materials: We used data of 193 children that was collected from Pediatric Urology Research Center of Children’s Hospital Medical Center, affiliated to Tehran University of Medical Sciences, Iran. The cause-specific and subdistribution hazard were computed. P < 0.05 was considered as statistically significant. R packages were used for analyzing the data. Results: Among these infants (36 girls, 157 boys), 117 (68%) cases had bilateral reflux as the event of interest. The variables “Sex” and “Direction of ANH (in bilateral level)” were significantly different (P