Economic and Radiation Costs of Screening Regimens for Vesico-Ureteral Reflux: a Decision Analysis
Jonathan C. Routh, MD1, Frederick D. Grant, MD1, Caleb P. Nelson, MD1, MPH, Fredrich H. Fahey, DSc2, A. Ted Treves, MD2 Richard S. Lee, MD1
1Children's Hospital Boston, Boston, MA, 2 Division of Nuclear Medicine, Children’s Hospital Boston, Boston, MA
The current standard for screening regimens following an initial febrile urinary infection is voiding cystourethrography (VCUG) and renal ultrasound (RUS). Recently, a competing protocol (Top-Down method: DMSA followed by VCUG for abnormal scans only) has been gaining increasing attention. The relative cost and radiation exposure of this method as compared to the standard regimen are unclear. We compared these screening regimens using formal decision analysis techniques, in the context of a child undergoing workup after an initial febrile UTI.
We constructed a decision tree model in order to evaluate two screening regimens: 1) standard (VCUG + RUS) vs. 2) Top-Down (DMSA +/- VCUG). We performed a Monte Carlo microsimulation analysis on a hypothetical cohort of 100,000 children of varying ages (0-10 years). All probability assumptions were based on published data, including: effective radiation dose estimates for continuous-fluoroscopy VCUG (cVCUG), pulsed-fluoroscopy VCUG (pVCUG) and DMSA scans, and radiation-induced solid tumor risk estimates. Cost estimates were modeled based on national billing data. Cost and radiation dosage estimates were based on one-time screening costs only. Sensitivity analyses were conducted around all probability estimates.
Screening 100,000 children with the Top-Down regimen resulted in a per-capita 7- to 10-fold increase in effective radiation dose if low-dose pVCUG was used. If high-dose cVCUG was used, the Top-Down approach resulted in a 1.7 to 2.6-fold increase in effective radiation dose. This excess radiation dose would be anticipated to produce an excess 0.2-0.5 radiation-induced solid tumors per 100,000 children screened. Top-Down was more expensive than standard regimen, with an excess cost of $9.3 million ($92.74 per patient). 4,744 patients with VUR would not have been detected using Top-Down, including 2,690 patients with Grade 3-5 VUR. These results proved robust on sensitivity analysis.
The Top-Down approach results in an increased per-capita cost and 2-10 fold increased effective radiation dose as compared to VCUG and RUS alone. Roughly 5% of VUR patients will be missed using the Top-Down approach, although the clinical consequences of these missed diagnoses are unclear.