Evaluation of Urinary Tract Dilation Classification System for Prediction of Long-Term Outcomes in Isolated Antenatal Hydronephrosis: A Cohort Study

Abstract

The aim of this study was to evaluate the performance of the new classification of urinary tract dilatation (UTD) to predict long-term clinical outcomes in infants with isolated antenatal hydronephrosis (ANH).Materials and Methods: Between 1989 and 2019, 447 infants diagnosed with isolated severe ANH and were prospectively followed. The main predictive variable for the analysis was the new UTD classification system. The events of interest were surgical interventions, urinary tract infections, chronic kidney disease stage II or higher, hypertension and proteinuria. The primary end-point was time until the occurrence of a composite event of renal injury, including proteinuria, hypertension and chronic kidney disease.Results: Among 447 infants with ANH included in the analysis, 255 (57%) had UTD P1, 93 (20.8%) UTD P2 and 99 (22.2%) UTD P3. Median followup time was 9 years (IQR 7e12 years). Of 447 patients included in the analysis, 11 (2.5%) had hypertension, 13 (2.9%) exhibited persistent mild proteinuria, 14 (3%) developed chronic kidney disease Stage 2 and 26 (5.8%) had the composite outcome of renal injury. By survival analysis, the UTD system predicted accurately all events of interest. According to the KaplaneMeier survival analysis, the probability of renal injury at 20 years of age was estimated at about 0%, 14% and 56% for patients assigned to UTD P1, UTD P2 and UTD P3, respectively (p <0.001).Conclusions: Our findings provide insights that the new UTD classification has a good performance for discriminating not only mid-term, but also long-term clinical outcomes, including renal injury.

Application of the postnatal urinary tract dilation classification system to predict the need for surgical intervention among neonates and young infants

“…In the present study, in concordance with previous studies [ 7 , 8 , 23 ], the UTD system appropriately stratified the risk of surgical intervention. Unlike this study, previous studies only included ureteropelvic junction obstruction–like hydronephrosis, excluding various conditions associated with ureteral or bladder abnormalities, such as VUR and posterior urethral valves; therefore, the wide spectrum of CAKUT was not evaluated using the UTD system [ 7 , 8 ]. Furthermore, the correlation of each US feature of the UTD system with the risk of surgical intervention was first analyzed.…”

“…Several studies have been conducted to validate the UTD system for predicting various clinical outcomes regarding surgical intervention [ 7 , 8 , 23 ], urinary tract infections [ 7 , 8 ], the resolution of UTD [ 24 ], and long-term renal injury [ 8 ]. In the present study, in concordance with previous studies [ 7 , 8 , 23 ], the UTD system appropriately stratified the risk of surgical intervention.…”

“…Several studies have been conducted to validate the UTD system for predicting various clinical outcomes regarding surgical intervention [ 7 , 8 , 23 ], urinary tract infections [ 7 , 8 ], the resolution of UTD [ 24 ], and long-term renal injury [ 8 ]. In the present study, in concordance with previous studies [ 7 , 8 , 23 ], the UTD system appropriately stratified the risk of surgical intervention. Unlike this study, previous studies only included ureteropelvic junction obstruction–like hydronephrosis, excluding various conditions associated with ureteral or bladder abnormalities, such as VUR and posterior urethral valves; therefore, the wide spectrum of CAKUT was not evaluated using the UTD system [ 7 , 8 ].…”

“…obstruction-like hydronephrosis, excluding various conditions associated with ureter or bladder abnormalities, such as VUR and PUV; therefore, the wide spectrum of CAKUT was not evaluated by the UTD system [7,8]. Besides, we first correlated each US feature of the UTD system with the risk of surgical intervention.…”

“…Several recent studies have assessed the ability of the UTD system to predict surgical interventions; however, those studies focused on ureteropelvic junction obstruction–like hydronephrosis and did not evaluate all of the UTD system’s US elements [ 7 , 8 ]. Other studies have shown that the UTD system yielded interobserver agreement data similar to or higher than those of the SFU system [ 9 , 10 ].…”