Prediction of vesico-ureteric reflux in childhood urinary tract infection:a multivariate approach

In this study, independent predictors obtained from patient history, physic al examination and laboratory results for vesico-ureteric reflux (VUR) in c hildren of 0-5 y with a first urinary tract infection (UTI) were assessed a nd the added value of renal ultrasound (US) investigated. Information was c ollected from children visiting the paediatric outpatient department with a first proven UTI, defined as a urine monoculture with greater than or equa l to 10(5) organisn/ml, with clinical symptoms and possible white cell coun t greater than or equal to 20 per high-power field of spun fresh urine. Chi ldren with neurologic bladder dysfunction were excluded. VUR was determined by voiding cystourethrography (VCUG) and graded from I to V. The diagnosti c value of predictors was judged using multivariate logistic modelling with the area under the receiver operating characteristic (ROC area). A risk sc orn was derived based on the regression coefficients of the independent pre dictors in the logistic model. In 140 children (51 boys and 89 girls) VUR w as diagnosed in 37. Independent predictors for VUR were male gender, age, f amily history for uropathology, serum C-reactive protein level (CRP) and di latation of the urinary tract on US. The ROC area of this model was 0.78 (9 5% CI: 0.69-0.87). This prediction model identified 12% (95% CI: 7-18) of t he patients without VUR without missing one case of VUR. If we used VUR gre ater than or equal to grade 3 as a threshold, the model assessed VUR to be absent in 34% (95% CI: 26-42). Conclusion: A prediction rule based on age, gender, family history, CRP and US results is useful in assessing the probability of VUR in the individual child with a first UTI and may help the physician to make decisions about performing additional imaging techniques. Prospective validation of the mod el in future patients, however, will be necessary before applying the rule in practice.