Neil Osterweil

May 28, 2014

ORLANDO, Florida — The use of recommended diagnostic tests declined within months of the publication of revised guidelines for the management of first-episode febrile urinary tract infection (UTI) in children, a new study shows.

The use of renal–bladder ultrasonography to detect reflux of urine into the ureter and kidneys decreased by 17%, and the use of voiding cystourethrogram to identify the severity of reflux plummeted by 42% after the American Academy of Pediatrics (AAP) guidelines were issued in 2011, said Andrew Kirsch, MD, clinical professor of urology at the Emory University School of Medicine in Atlanta.

"The decreased ultrasound use is very concerning to pediatricians, to nephrologists, and to urologists, particularly because there is a strong association with hospitalization. But what we consider an even bigger factor is that we may be missing other diagnoses," he explained here at the American Urological Association 2014 Annual Scientific Meeting.

The Guidelines

About 1% of all office visits by children are related to UTIs, as are about 10% of all emergency department visits. Approximately 15% of children with UTIs will develop renal scarring, and the risk of scarring rises as the number of recurrent UTIs increases, Dr. Kirsch reported.

The most common cause of UTI in children is vesicoureteral reflux, which accounts for about 40% of cases, he said.

The UTI guidelines unequivocally state that "febrile infants with UTI should undergo renal and bladder ultrasonography" (Pediatrics. 2011;128:595-610).

They also state that voiding cystourethrogram "should not be performed routinely after the first febrile UTI," but is warranted if ultrasound shows hydronephrosis, renal scarring, or findings that indicate high-grade vesicoureteral reflux or an obstructive uropathy.

But the guidelines do not take into account results from trials conducted in Sweden and the United States that involved a combined total of 810 children with vesicoureteral reflux.

The Swedish reflux trial showed that antibiotic prophylaxis and endoscopic injection were more effective than observation in preventing febrile UTIs, and that there is a strong correlation between febrile UTIs and the risk of new renal scarring (J Urol. 2010;184:280-285).

More recently, the American RIVUR trial showed that antimicrobial prophylaxis in children with vesicoureteral reflux is associated with a 50% reduction in the risk for recurrent UTI (N Engl J Med. Published online May 4, 2014). In that study, the researchers conclude that the findings might warrant reconsideration of the AAP recommendation to omit voiding cystourethrogram after first-episode febrile UTI.

Before and After Review

To see what effects the guidelines had on imaging studies in young children with febrile UTI, Dr. Kirsch's team looked at emergency department visits for febrile UTI at Emory from January to June 2011, before the guidelines were published, and from January to June 2012, after publication.

They looked at patient demographics (age and sex), urine culture and lab results, radiographic studies, and admission/discharge status. Patients with a history of febrile UTI, known reflux, or other urologic problems were excluded from the analysis. Patients ranged in age from 2 months to 2 years.

All of these children should have been examined with renal–bladder ultrasound, Dr. Kirsch pointed out, but use decreased from 75.6% in the 2011 cohort to 58.4% in the 2012 cohort (P < .001).

Despite this decline, the proportion of abnormal findings was not significantly different in the 2011 and 2012 cohorts (28.5% vs 23.1%).

Similarly, the use of voiding cystourethrogram decreased from 2011 to 2012 (72.1% vs 38.2%; P < .001).

The risk for vesicoureteral reflux was not significantly different from 2011 to 2012 (36.3% vs 38.2%), nor was reflux severity (mean maximum grade, 2.9 vs 2.5).

These findings show that although physicians are following the recommendations for voiding cystourethrograms, selective use of cystourethrogram on the basis of ultrasound results did not identify higher grades of vesicoureteral reflux.

"We're just missing the same patients," said Dr. Kirsch.

Abnormal ultrasound findings did not accurately predict the presence of reflux. It identified only 36.4% of cases later proven to be reflux, and falsely identified reflux in 24.8% of cases without reflux.

In addition, the reduced use of cystourethrogram resulted in more cases of moderate to severe vesicoureteral reflux being missed in the 2012 cohort than in the 2011 cohort.

Abnormal ultrasounds, being male, and being younger were independently associated with risk for hospitalization. Reflux grade did not differ between patients who were admitted to the hospital and those discharged from the emergency department.

Foregoing the routine use of voiding cystourethrogram, as recommended in the guidelines, "sends a dangerous message to referring physicians that somehow reflux and other things we see on ultrasound are really not important. We believe there is going to be increased morbidity due to undiagnosed reflux," Dr. Kirsch said.

"Applying the UTI guidelines to young children, particularly in the emergency room setting, requires careful reconsideration," he concluded.

In the 1970s, vesicoureteral reflux was the most common cause of kidney failure in the pediatric population, said Anthony Atala, MD, chair of the Department of Urology at Wake Forest Baptist Medical Center in Winston-Salem, North Carolina, who was not involved in the study.

"Over the past few decades, there has been such an improvement in the management of reflux that people forget that undiagnosed and untreated reflux can be really bad for you," he told Medscape Medical News.

American Urological Association (AUA) 2014 Annual Scientific Meeting: Abstract MP44-03. Presented May 18, 2014.

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