Retrospective analysis of inflammatory parameters in acute pyelonephritis

Different parameters were compared in children with acute pyelonephritis in order to facilitate the early detection of vesicoureteral reflux (VUR) in primary healthcare settings.

This was a cross-sectional, hospital-based study. A total of 149 children with confirmed acute pyelonephritis were retrospectively analyzed between January 1999 and December 2000. The primary factors studied were body temperature, C-reactive protein level, white blood cell count and neutrophil ratio.

The study population comprised 82 males (55.0%) and 67 females (45.0%). The mean age of the patients was 2.7 +/- 3.9 years (age range 1 day to 18 years; 75% <3 years old). Of 123 patients who underwent voiding cystourethrography, 34 (27.6%) had VUR. When raised C-reactive protein, leukocytosis and raised neutrophil ratio occurred together, the specificity and positive predictive value for predicting VUR were obviously increased, but sensitivity was radically decreased. After controlling for the other covariates, multivariate logistic regression analysis showed that factors significantly related to VUR were age (odds ratio = 1.3, 95% confidence interval 1.02-1.67; p < 0.05) and raised neutrophil ratio (odds ratio = 4.2, 95% confidence interval 1.1-16.5; p < 0.05).

Our findings emphasize that the prevalence of VUR in children with acute pyelonephritis is extremely high. If a raised neutrophil ratio is observed, the potential risk of VUR is significantly increased in patients with clinically suspected acute pyelonephritis. Hence, the neutrophil ratio is recommended as an excellent parameter for predicting VUR.