Cost-effectiveness analysis of optimal diagnostic strategy for patients with symptomatic cholelithiasis with intermediate probability for choledocholithiasis

Background and aims: EUS, MRCP, and intraoperative cholangiogram (IOC) are the recommended diagnostic modalities for patients with intermediate probability for choledocholithiasis (IPC). The relative cost-effectiveness of these modalities in patients with cholelithiasis and IPC is understudied.

Methods: We developed a decision tree for diagnosing IPC (base-case probability, 50%; range, 10%-70%); patients with a positive test were modeled to undergo therapeutic ERCP. The strategies tested were laparoscopic cholecystectomy with IOC (LC-IOC), MRCP, single-session EUS + ERCP, and separate-session EUS + ERCP. Costs and probabilities were extracted from the published literature. Effectiveness was assessed by assigning utility scores to health states, average proportion of true-positive diagnosis of IPC, and the mean length of stay (LOS) per strategy. Cost-effectiveness was assessed by extrapolating a net-monetary benefit (NMB) and average cost per true-positive diagnosis.

Results: LC-IOC was the most cost-effective strategy to diagnose IPC (base-case probability of 50%) among patients with cholelithiasis in health state-based effectiveness analysis (NMB of $34,612), diagnostic test accuracy-based effectiveness analysis (average cost of $13,260 per true-positive diagnosis), and LOS-based effectiveness analysis (mean LOS of 4.13) compared with strategies 2 (MRCP), 3 (single-session EUS + ERCP), and 4 (separate-session EUS + ERCP). These findings were robust on deterministic and probabilistic sensitivity analyses.

Conclusions: For patients with cholelithiasis with IPC, LC-IOC is a cost-effective approach that should limit preoperative testing and may shorten hospital LOS. Our findings may be used to design institutional and organizational management protocols.