Delayed Treatment Linked to Renal Scarring in Children with UTIs

For children with febrile urinary tract infections (UTIs), the risk of new renal scarring increases with each hour of delay to antimicrobial treatment, suggests a study in JAMA Pediatrics.

The retrospective analysis included data on 482 children from two previous longitudinal studies. Both studies included 2- to 72-month-old children (median age 11 months) with their first or second UTI. Ninety percent of children were girls and 78% had vesicoureteral reflux. Duration of fever before the start of antimicrobial therapy was analyzed for association with new renal scarring, based on the finding of photopenia plus contour change on a dimercaptosuccinic acid renal scan at two-year follow-up.

New renal scarring occurred in 7.2% of children. Delays to antimicrobial therapy were associated with renal scarring. Median duration of fever before the start of antimicrobial treatment was 72 hours in children with renal scarring versus 48 hours in those without scarring.

The association remained significant after adjustment for age, race/ethnicity, bacterial cause, and previous or interim UTIs. For each hour’s delay to antimicrobial therapy, there was a 0.8% increase in the odds of new renal scarring. Number of segments with renal scarring was independently associated with height of fever and interim UTIs, but not with delay to treatment.

Delays to antibiotic treatment have been suggested to increase the risk and extent of renal scarring in children with febrile UTIs. The new results indicate that delaying treatment for 48 hours or longer increased the odds of new renal scarring by nearly 50%. The investigators conclude, “[C]linicians should not delay testing in febrile children who could potentially have a UTI” [Shaikh N, et al. Early antibiotic treatment for pediatric febrile urinary tract infection and renal scarring. JAMA Pediatr 2016; 170:848–854].