- In this retrospective cohort study, delay in staring antimicrobials in pediatric patients under 6yrs of age with febrile urinary tract infections (UTI) was associated with renal scarring.
- The median duration of fever prior to antimicrobial start was 72 hours in those with renal scarring and 48 hours in those without renal scarring.
Evidence Rating Level: 2 (Good)
Study Rundown: There is debate that a delay in antimicrobial therapy for children with febrile UTIs may lead to scarring of the kidneys. However, studies have had conflicting results. This retrospective cohort study aimed to determine whether a delay in the initiation of antimicrobial therapy for febrile UTIs is associated with the occurrence and severity of renal scarring.
Delaying the start of antimicrobials in pediatric febrile UTI was significantly associated with renal scarring despite adjustment for potential confounding variables. Median duration of fever prior to initiating antimicrobials was 72 hours in those with renal scarring and 48 hours in those without renal scarring. Strengths of this study included combing two cohort populations to increase the power. A major limitation was the use of parental recollection to determine the duration of fever prior to treatment, which significantly impacted the validity of the results since time of fever was the main “exposure” variable.
Relevant Reading: Does Early Treatment of Urinary Tract Infection Prevent Renal Damage?
In-Depth [retrospective cohort]: This study was conducted using data from 2 longitudinal studies: Randomized Intervention for Children with Vesicoureteral Reflux and the Careful Urinary Tract Infection Evaluation Study. Children in these two studies were aged 2 to 72 months and presented after their first or second UTI at primary or specialty care settings across the USA. They were followed for 2 years. The exposure of interest was the child’s fever duration prior to initiation of antimicrobial therapy for the index UTI. This was determined by parental recollection of fever duration. The outcome of interest was new renal scarring determined by the evidence of photopenia and contour change on a dimercaptosuccinic acid renal scan that was not present at baseline.
Of the 482 children included in the analysis, 90% were female. The median age was 11 months. Thirty-five children developed new renal scarring. Delay in starting antimicrobials was statistically associated with new renal scarring. Those who did not develop renal scarring had a median duration (25th, 75th percentile) of fever of 48 (24,72) hours and those with renal scarring had a median duration of fever of 72 (30,120) hours, P=0.003. Older age (OR 1.03; 95% CI 1.01-1.05), Hispanic ethnicity (OR 5.24; 95% CI 2.15-12.77), and bladder and bowel dysfunction (OR 6.44, 95% CI 2.89-14.38) were also associated with new renal scarring.
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