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Abstract: FR-PO1095

Which Grading System Is More Useful to Estimate the Time to Resolution of Isolated Hydronephrosis Between SFU and APPD Grades? A Single-Center Study

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Jung, Jiwon, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea (the Republic of)
  • Lee, Joo Hoon, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea (the Republic of)
  • Park, Young seo, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, Korea (the Republic of)
Background

Predicting the time to resolution of isolated hydronephrosis is an important topic for both clinicians and families. Because the Society for Fetal Urology(SFU) classification and Anterior-Posterior Pelvic Diameter(APPD) are the two most commonly used grading tools of hydronephrosis, we aimed to compare the ability of two systems in estimating resolution rate.

Methods

We retrospectively reviewed medical records of patients with isolated hydronephrosis prenatally detected and postnatally diagnosed between 1990-2018, and excluded patients with pyeloplasty, vesicoureteral reflux or other anomalies. SFU grade and APPD at first USG were collected and APPD ranges of 5–9mm, 10–14mm, 15–19mm, and above 20mm were classified as grade 1, 2, 3 and 4. Resolution was defined as APPD below 5mm with SFU grade 1. Log rank test and Kaplan-Meier curves were used to analyze time to resolution of each SFU and APPD grades.

Results

Of 432 patients(544 renal units), 382(88.4%) were male, and 398(73.2%) renal units were left sided. 217(39.9%) units reached resolution at a mean follow-up of 51±44 months. SFU grades 1 through 4 showed resolution rate of 80.0%, 60.2%, 48.0%, 20.0% respectively, and APPD grades showed resolution rate of 78.0%, 44.3%, 25.7%, 6.7% respectively at 48 months. There was discrepancy between SFU and APPD grades in 253(46.5%) units. In each disproportional case, resolution rate approximated to the rate of APPD grade without significant difference. In proportional cases, the cumulative resolution rate of each pair of grade 1 and 2(84.5%, 52.7%) approached the rate of each APPD grade(84.1%, 59.7%), while SFU grade 3 with APPD grade 3 showed a value of resolution rate(48.1%) between the resolution rate of each SFU(69.8%) and APPD(25.7%) grade.

Conclusion

APPD grade is more useful than SFU grade in predicting time to resolution when there is discrepancy between two grades. In the low grade concordant cases, prediction of time to resolution can be resonably based on APPD.