The Vesicoureteral Reflux Index (VURx) is a clinical scoring system designed to predict the likelihood of spontaneous resolution or significant improvement in children with primary vesicoureteral reflux (VUR) (Arlen et al., 2016; Kirsch et al., 2014). First introduced as a tool for children diagnosed under the age of two, it has since been validated for older children and serves as a critical guide for individualized management plans in pediatric urology (Arlen et al., 2017; Kirsch et al., 2014).

The VURx Scoring System

The VURx score is calculated based on four specific variables identified during a diagnostic voiding cystourethrogram (VCUG) and the patient’s gender (Kirsch et al., 2014). The cumulative score ranges from 1 to 6 points.

Scoring Criteria

The points are assigned based on the following clinical and radiographic findings:

(Source: Kirsch et al., 2014; Baltrak et al., 2024)

Predictive Power and Clinical Outcomes

The primary utility of the VURx is its ability to categorize patients by their probability of spontaneous resolution within a two-year timeframe. Studies have shown a strong inverse correlation between the VURx score and the rate of improvement (Arlen et al., 2016).

• VURx 1: ~88–89% resolution/improvement rate.
• VURx 3: ~53–62% resolution/improvement rate.
• VURx 5+: ~11–14% resolution/improvement rate (Arlen et al., 2016; Kirsch et al., 2014).

Breakthrough UTIs

Beyond resolution, a higher VURx score is a significant predictor of breakthrough febrile urinary tract infections (fUTI) (Arlen et al., 2020). Research indicates that VURx may be more accurate than the standard International Reflux Grade alone in predicting which children are at risk for recurrent infections while on antibiotic prophylaxis (Arlen et al., 2020).

Clinical Significance

The VURx provides a more nuanced approach than traditional grading. By incorporating the timing of the reflux (when the reflux occurs during bladder filling), it captures the physiological severity of the condition (Kirsch et al., 2014).

• Low VURx (1–2): Patients are excellent candidates for observation and conservative management, as spontaneous resolution is highly likely (Arlen et al., 2016).
• High VURx (4–6): These children are less likely to experience resolution and have a higher risk of surgical intervention or breakthrough infections, often necessitating earlier discussions regarding anti-reflux surgery (Arlen et al., 2016; Arlen et al., 2020).

References

Arlen, A. M., Garcia-Roig, M., Weiss, A. D., Leong, T., Cooper, C. S., & Kirsch, A. J. (2016). Vesicoureteral Reflux Index: 2-Institution Analysis and Validation. Journal of Urology, 195(4), 1294-1299. https://doi.org/10.1016/j.juro.2015.03.094

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Arlen, A. M., Leong, T., Wu, C. Q., Traore, E. J., Cooper, C. S., & Kirsch, A. J. (2020). Predicting Breakthrough UTI: Comparative Analysis of VUR Index (VURx), VUR Grade and Ureteral Diameter Ratio (UDR). Journal of Urology, 204(6), 1-6.

(Note: Source data retrieved from clinician guidance summaries; see full paper for DOI).

Baltrak, Y. A., Akdoğan, N., Değer, M., Izol, V., Aridoğan, I. A., & Satar, N. (2024). An evaluation of ureteral diameter ratio and vesicoureteral reflux index in the treatment of primary vesicoureteral reflux. Asian Journal of Urology, 11(3), 437-442. https://doi.org/10.1016/j.ajur.2023.05.007

Cited by: 1

Kirsch, A. J., Arlen, A. M., Leong, T., Merriman, L. S., Herrel, L. A., Scherz, H. C., Smith, E. A., & Srinivasan, A. K. (2014). Vesicoureteral reflux index (VURx): A novel tool to predict primary reflux improvement and resolution in children less than 2 years of age. Journal of Pediatric Urology, 10(6), 1249-1254. https://doi.org/10.1016/j.jpurol.2014.06.019

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