Top-Down versus Bottom-Up Approach in Children Presenting with Urinary Tract Infection: Comparative Effectiveness
Hsin-Hsiao Scott Wang1, Dylan Cahill2, John Panagides2
1Department of Urology, Boston Children's Hospital, Boston, Massachusetts.
Insights
The top-down imaging approach for pediatric urinary tract infections (UTIs) may lead to slightly more recurrent UTIs but significantly reduces the need for voiding cystourethrogram (VCUG) and continuous antibiotic prophylaxis (CAP). This comparative analysis informs optimal diagnostic strategies for children with UTIs.
Area of Science:
- Pediatric Nephrology
- Diagnostic Imaging
- Infectious Diseases
Background:
- Initial imaging strategies for pediatric urinary tract infections (UTIs) remain a subject of debate.
- Current approaches include renal/bladder ultrasound with voiding cystourethrogram (VCUG) (bottom-up) or dimercaptosuccinic acid (DMSA) scan (top-down).
- Comparative effectiveness data between these diagnostic pathways are limited.
Purpose of the Study:
- To conduct a comparative effectiveness analysis of the top-down versus bottom-up imaging approaches for pediatric UTIs.
- To evaluate the impact of each approach on recurrent UTIs, utilization of VCUG, and exposure to continuous antibiotic prophylaxis (CAP).
Main Methods:
- A simulation using 1,000 hypothetical sets of 500 children based on RIVUR/CUTIE trial data.
- Top-down approach: Initial DMSA scan, followed by VCUG only if renal scarring is present.
- Bottom-up approach: Initial VCUG, with assumed continuous antibiotic prophylaxis (CAP) for all children with vesicoureteral reflux (VUR).
Main Results:
- The top-down approach was associated with a statistically significant increase in recurrent UTIs compared to the bottom-up approach (24.4% vs 18.0%, p=0.045).
- The bottom-up approach led to significantly more VCUGs (100% vs 2.4%, p <0.001).
- The top-down approach substantially reduced CAP exposure (0.4% vs 25% of patients, and 162 vs 5 days/person, p <0.001).
Conclusions:
- The top-down imaging approach for pediatric UTIs is linked to a slightly higher rate of recurrent infections.
- However, the top-down strategy significantly decreases the necessity for VCUG and reduces exposure to continuous antibiotic prophylaxis (CAP).
- These findings provide valuable insights for optimizing diagnostic pathways in pediatric UTI management.
Purpose:
The initial imaging approach to children with urinary tract infection (UTI) is controversial. Along with renal/bladder ultrasound, some advocate voiding cystourethrogram (VCUG), ie a bottom-up approach, while others advocate dimercaptosuccinic acid (DMSA) scan, ie a top-down approach. Comparison of these approaches is challenging. In the RIVUR/CUTIE trials, however, all subjects underwent both VCUG and DMSA scan. Our objective was to perform a comparative effectiveness analysis of the bottom-up vs top-down approach.
Materials And Methods:
We simulated 1,000 hypothetical sets of 500 children using RIVUR/CUTIE data. In the top-down approach, patients underwent initial DMSA scan, and only those with renal scarring underwent VCUG. In the bottom-up approach, the initial study was VCUG. We assumed all children with vesicoureteral reflux (VUR) received continuous antibiotic prophylaxis (CAP). Outcomes included recurrent UTI, number of VCUGs and CAP exposure. We assumed a 25% VUR prevalence in children with initial UTI with sensitivity analysis using 40% VUR prevalence.
Results:
Median age of the original RIVUR/CUTIE cohort was 12 months. First DMSA scan was performed at a median of 8.2 weeks (IQR 5-11.8) after the index UTI. In the simulated cohort, slightly higher yet statistically significantly recurrent UTI was associated with the top-down compared with the bottom-up approach (24.4% vs 18.0%, p=0.045). On the other hand, the bottom-up approach resulted in more VCUG (100% vs 2.4%, p <0.001). Top-down resulted in fewer CAP-exposed patients (25% vs 0.4%, p <0.001) and lower overall CAP exposure (5 vs 162 days/person, p <0.001). Sensitivity analysis was performed with 40% VUR prevalence with similar results.
Conclusions:
The top-down approach was associated with slightly higher recurrent UTI. Compared to the bottom-up approach, it significantly reduced the need for VCUG and CAP.
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