Prediction of high-grade vesicoureteral reflux after pediatric urinary tract infection: external validation study of procalcitonin-based decision rule

• Published in: PloS one 2011-12, Vol.6 (12), p.e29556-e29556
• Main Authors: Leroy, Sandrine, Bouissou, François, Fernandez-Lopez, Anna, Gurgoze, Metin K, Karavanaki, Kyriaki, Ulinski, Tim, Bressan, Silvia, Vaos, Geogios, Leblond, Pierre, Coulais, Yvon, Cubells, Carlos Luaces, Aygun, A Denizmen, Stefanidis, Constantinos J, Bensman, Albert, Da Dalt, Liviana, DaDalt, Liviana, Gardikis, Stefanos, Bigot, Sandra, Gendrel, Dominique, Bréart, Gérard, Chalumeau, Martin
• Format: Article
• Language: English
• Subjects: Analysis; Bacterial infections; Calcitonin - blood; Calcitonin Gene-Related Peptide; Child; Child health; Children; Children & youth; Complications and side effects; Cytokines; Decision Making; Derivation; Female; Humans; Infection; Infections; Inflammation; Male; Medical research; Medicine; Nephrology; Patients; Pediatrics; Predictions; Procalcitonin; Prospective Studies; Protein Precursors - blood; Quality; Reproducibility; Secondary analysis; Sensitivity; Sensitivity and Specificity; Ultrasonic imaging; University faculty; Urinary tract; Urinary tract diseases; Urinary tract infections; Urinary Tract Infections - blood; Urinary Tract Infections - complications; Urogenital system; Vesico-Ureteral Reflux - blood; Vesico-Ureteral Reflux - complications; Vesico-Ureteral Reflux - diagnosis
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0029556

Predicting vesico-ureteral reflux (VUR) ≥3 at the time of the first urinary tract infection (UTI) would make it possible to restrict cystography to high-risk children. We previously derived the following clinical decision rule for that purpose: cystography should be performed in cases with ureteral dilation and a serum procalcitonin level ≥0.17 ng/mL, or without ureteral dilatation when the serum procalcitonin level ≥0.63 ng/mL. The rule yielded a 86% sensitivity with a 46% specificity. We aimed to test its reproducibility. A secondary analysis of prospective series of children with a first UTI. The rule was applied, and predictive ability was calculated. The study included 413 patients (157 boys, VUR ≥3 in 11%) from eight centers in five countries. The rule offered a 46% specificity (95% CI, 41-52), not different from the one in the derivation study. However, the sensitivity significantly decreased to 64% (95%CI, 50-76), leading to a difference of 20% (95%CI, 17-36). In all, 16 (34%) patients among the 47 with VUR ≥3 were misdiagnosed by the rule. This lack of reproducibility might result primarily from a difference between derivation and validation populations regarding inflammatory parameters (CRP, PCT); the validation set samples may have been collected earlier than for the derivation one. The rule built to predict VUR ≥3 had a stable specificity (ie. 46%), but a decreased sensitivity (ie. 64%) because of the time variability of PCT measurement. Some refinement may be warranted.