Prediction of moderate and high grade vesicoureteral reflux after a first febrile urinary tract infection in children: construction and internal validation of a clinical decision rule.

PURPOSE: Urinary tract infection leads to a diagnosis of moderate or high grade (III or higher) vesicoureteral reflux in approximately 15% of children. Predicting reflux grade III or higher would make it possible to restrict cystography to high risk cases. We aimed to derive a clinical decision rule to predict vesicoureteral reflux grade III or higher in children with a first febrile urinary tract infection. MATERIALS AND METHODS: We conducted a secondary analysis of prospective series including all children with a first febrile urinary tract infection from the 8 European participating university hospitals. RESULTS: A total of 494 patients (197 boys, reflux grade III or higher in 11%) were included. Procalcitonin and ureteral dilatation on ultrasound were significantly associated with reflux grade III or higher and then combined into a prediction model with an ROC AUC of 0.75 (95% CI 0.69-0.81). Given the prespecified constraint of achieving at least 85% sensitivity, our model led to the clinical decision rule, for children with a first febrile urinary tract infection cystography should be performed in cases with ureteral dilatation and serum procalcitonin level 0.17 ng/ml or higher, or without ureteral dilatation (ie ureter not visible) when serum procalcitonin level is 0.63 ng/ml or higher. The rule had 86% sensitivity (95% CI 74-93) with 47% specificity (95% CI 42-51). Internal cross-validation produced 86% sensitivity (95% CI 79-93) and 43% specificity (95% CI 39-47). CONCLUSIONS: A clinical decision rule was derived to enable a selective approach to cystography in children with urinary tract infection. The rule predicts high grade vesicoureteral reflux with approximately 85% sensitivity and avoids half of the cystograms that do not find reflux grade III or higher. Further validation is needed before its widespread use.

Procalcitonin to reduce the number of unnecessary cystographies in children with a urinary tract infection: a European validation study.

OBJECTIVE: To validate high serum procalcitonin (PCT) as a predictor of vesicoureteral reflux (VUR) in children with a first febrile urinary tract infection (UTI). STUDY DESIGN: This secondary analysis of prospective hospital-based cohort studies included children ages 1 month to 4 years with a first febrile UTI. RESULTS: Of the 398 patients included in 8 centers in 7 European countries, 25% had VUR. The median PCT concentration was significantly higher in children with VUR than in those without: 1.6 versus 0.7 ng/mL (P = 10(-4)). High PCT (> or =0.5 ng/mL) was associated with VUR (OR: 2.3; 95% CI, 1.3 to 3.9; P = 10(-3)). After adjustment for all cofactors, the association remained significant (OR: 2.5; 95% CI, 1.4 to 4.4; P = 10(-3)). The strength of the relation increased with the grade of reflux (P = 10(-5)). The sensitivity of procalcitonin was 75% (95% CI, 66 to 83) for all-grade VUR and 100% (95% CI, 81 to 100) for grade > or =4 VUR, both with 43% specificity (95% CI, 37 to 48). CONCLUSIONS: High PCT is a strong, independent and now validated predictor of VUR that can be used to identify low-risk patients and thus avoid one third of the unnecessary cystourethrographies in children with a first febrile UTI.