Objectives: Our prospective clinical study of prospectively compared physicians' management of submucosal tumors (SMTs) with and without endoscopic ultrasound (EUS). It showed that EUS reduced further tests by more than 50%, but it is unclear whether it reduced the overall costs. The aim of this study was to determine whether EUS would reduce costs.
Methods: Based on the data from the clinical study, a decision analysis was created to compare the direct hospital costs for diagnosing SMTs with and without EUS. Cost data from Germany, Canada, Japan, France, and the United States were used. Costs were expressed as a ratio of the cost of esophagogastroduodenoscopy (EGD). Average cost ratios for each procedure were as follows (sensitivity analysis ranges are 95% CIs): EGD = 1; large particle biopsy (LPB) 0.75 (0.22-1.24); endoscopic ultrasound (EUS) 2.0 (1.22-2.79); abdominal ultrasound (US) 0.77 (0.31-1.24); computed tomography (CT) 1.79 (0.64-2.95); magnetic resonance imaging (MRI) 3.54 (1.28-5.79); and ERCP 3.45 (0.82-6.07).
Results: Initial inputs show the "no EUS" strategy is less costly when cost data for all countries are averaged (expected cost 2.13 vs 2.71, expressed as a ratio of the cost of EGD]) and for all countries individually except Germany. In descending order, overall management costs were most sensitive to the relative costs of CT and EUS, the cost of LPB, and to the probability of no further testing when the "no EUS" strategy is used. However, threshold analysis showed that changes in only one variable, the ratio of the cost of EUS compared to CT (the "EUS/CT ratio"), were able to shift the optimal strategy from "no EUS" to "EUS." "EUS" becomes less costly only if the EUS/CT cost ratio is <0.85 (i.e., if the cost of EUS is <85% that of CT). If the potential for EUS to reduce severe complications caused by LPB of high risk lesions is incorporated, "EUS" is less costly if this risk is >2% (range 1-5%).
Conclusions: When used to diagnose SMTs, EUS may reduce the need for further tests but not necessarily costs. For this indication, the relative cost of EUS compared with CT is what most limits its potential value as a cost-minimizing test. The costs, economic impact, and hence the relative appropriateness of EUS and other procedures may vary in different health care systems.