Development of visual scoring system with Tc-99m DMSA renal scintigraphy to predict the risk of recurrence of symptomatic urinary tract infections in pediatric patients

Objective: Vesicoureteral reflux (VUR) is a major risk factor for recurrent symptomatic urinary tract infection (UTI) in pediatric patients. In addition, dimercaptosuccinic acid renal scintigraphy (DMSA) is an important diagnostic modality of VUR. However, the value of DMSA for predicting recurrent pediatric UTI has not been studied. Therefore, we aimed to develop visual scoring system (VSS) with DMSA to predict the risk of recurrence of symptomatic urinary tract infection in pediatric patient under the age of 24 months. Methods: Pediatric UTI patients who visited our tertiary hospital emergency department and underwent DMSA for initial work-up from January 2006 to December 2014 were reviewed retrospectively. We developed a VSS with Tc-99m DMSA renal scintigraphy. We compared sensitivity and specificity between VSS with DMSA and other variables in predicting recurrent symptomatic UTI. Laboratory indices for systemic inflammation, abnormal finding on ultrasonography, VUR on voiding cystourethrogram (VCUG), and the VSS with DMSA were considered as variables. In addition, we used Kaplan–Meier estimator analyses and Cox proportional regression analyses to evaluate the predictive value of each variable for the recurrence of symptomatic UTI. Results: A total of 338 patients were enrolled. During the follow-up period, 42 patients (12.4%) had UTI recurrence. Visual scoring with DMSA resulted in 69.1% sensitivity and 79.4% specificity with an optimal cut-off value of score 2 (AUC = 0.790, p < 0.001). Significant predictive factors associated with recurrent symptomatic UTI were CRP ≥ 67.0 mg/L, VUR on VCUG and VSS with DMSA ≥ score 2. On multivariate analysis, the visual score with DMSA was the only independent prognostic factor for recurrent symptomatic UTI (p < 0.001; adjusted hazard ratio = 7.522; 95% CI = 2.799–20.224). Conclusion: High scores in VSS with DMSA were associated with frequent recurrence and short recurrence periods in pediatric UTI patients. VSS with DMSA can stratify risk of recurrence in pediatric UTI patients.