Reliability of grading of vesicoureteral reflux and other findings on voiding cystourethrography.
BACKGROUND
Voiding cystourethrography (VCUG) is the modality of choice to diagnose vesicoureteral reflux (VUR). Although grading of VUR is essential for prognosis and clinical decision-making, the inter-observer reliability for grading has been shown to vary substantially. The Randomized Intervention for Children with VesicoUreteral Reflux (RIVUR) trial provides a large cohort of children with VUR to better understand the reliability of VCUG findings.


OBJECTIVE
To determine the inter-observer consistency of the grade of VUR and other VCUG findings in a large cohort of children with VUR.


METHODS
The RIVUR trial is a randomized controlled trial of antimicrobial prophylaxis in children with VUR diagnosed after UTI. Each enrollment VCUG was read by a local clinical (i.e. non-reference) radiologist, and independently by two blinded RIVUR reference radiologists. Reference radiologists' disagreements were adjudicated for trial purposes. The grade of VUR and other VCUG findings were extracted from the local clinical radiologist's report. The unit of analysis included individual ureters and individual participants. We compared the three interpretations for grading of VUR and other VCUG findings to determine the inter-observer reliability.


RESULTS
Six-hundred and two non-reference radiology reports from 90 institutions were reviewed and yielded the grade of VUR for 560 left and 524 right ureters. All three radiologists agreed on VUR grade in only 59% of ureters; two of three agreed on 39% of ureters; and all three disagreed on 2% of ureters (Table). Agreement was better (≥92%) for other VCUG findings (e.g. bladder shape "normal"). The non-reference radiologists' grade of VUR differed from the reference radiologists' adjudicated grade by exactly one grade level in 19% of ureters, and by two or more grade levels in 2.2% of ureters. When the participant was the unit of analysis, all three radiologists agreed on the grade of VUR in both ureters in just 43% of cases.


CONCLUSIONS
Our study shows considerable and clinically relevant variability in grading VUR by VCUG. This variability was consistent when comparing non-reference to the adjudicated reference radiologists' assessment and the reference radiologists to each other. This study was limited to children with a history of UTI and grade I-IV VUR and may not be generalizable to all children who have a VCUG.


CONCLUSIONS
The considerable inter-observer variability in VUR grading has both research and clinical implications, as study design, risk stratification, and clinical decision-making rely heavily on grades of VUR.
Department of Surgery, Division of Pediatric Urology, University of Utah School of Medicine, Salt Lake City, UT, USA. Electronic address: aschaeffer78@gmail.com.
Anthony J
AJ
Schaeffer
Department of Pediatric Urology, Women & Children's Hospital of Buffalo, Buffalo, NY, USA.
Saul P
SP
Greenfield
Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Anastasia
A
Ivanova
Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Gang
G
Cui
Department of Radiology, Children's Hospital of Michigan, Detroit, MI, USA.
J Michael
JM
Zerin
Department of Urology, Boston Children's Hospital, Boston, MA, USA; Department of Radiology, Boston Children's Hospital, Boston, MA, USA.
Jeanne S
JS
Chow
Department of Pediatrics, Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
Alejandro
A
Hoberman
Department of Urology, Johns Hopkins Hospital, Baltimore, MD, USA.
Ranjiv I
RI
Mathews
Department of Pediatrics, Children's Hospital of Michigan, Detroit, MI, USA.
Tej K
TK
Mattoo
Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
Myra A
MA
Carpenter
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
Marva
M
Moxey-Mims
Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, USA.
Russell W
RW
Chesney
Department of Urology, Boston Children's Hospital, Boston, MA, USA.
Caleb P
CP
Nelson
D002648:Child; D002675:Child, Preschool; D000070621:Cystography / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014481:United States; D014521:Urethra / Q000000981:diagnostic imaging*; D014718:Vesico-Ureteral Reflux / Q000000981:diagnostic imaging* / Q000503:physiopathology*
Classification; Concordance; Radiology; Urinary tract infection; Vesico-ureteral reflux; Voiding cystourethrogram
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