Symptomatic recurrence rate of upper urinary tract calculi in children after endourological procedures

Introduction The recurrence rate of paediatric urolithiasis was less reported, especially in Asians. Our aim was to verify the symptomatic recurrence rate of Chinese paediatric urolithiasis and to determine the predictive factors for stone recurrence. Materials and methods We performed a retrospective review of children who presented with first upper urinary tract calculi from June 2014 to September 2019. For the follow-up, we generated Kaplan-Meier plots with time to stone recurrence and Cox proportional hazard regression analyses were applied. The recurrence was defined as a new symptomatic stone on ultrasound and/or computerized tomography. Results A total of 230 children with a median age of 5 yr (IQR 4-8) were included. Calcium oxalate was found in 72% of stones, and calcium apatite was found in 32% of stones. After a median follow-up of 39.5 months, 34 (14.8%) children had stone recurrence. Median time to stone recurrence was 31 months. Among them, 31 (91.2%) required surgical intervention. Older children (P < 0.01), higher BMI (HBM) (P < 0.01) and higher stone burden (P < 0.01) were shown to be associated with stone recurrence in the univariate analysis. The multivariate Cox regression analysis showed that children with stone burden > 2 cm(3) had a higher risk of recurrence (HR 4.84, 95%CI 2.28-10.3). Children with HBM had an increased recurrence rate compared to normal BMI children (HR 2.99, 95%CI 1.36-6.56). Conclusions The symptomatic recurrence rate of paediatric urolithiasis in Chinese is not as high as that reported in Caucasians. HBM and higher stone burden are associated with higher recurrence rates.