Intra-Operative vs Pre-Operative Endoscopic Sphincterotomy in Patients with Gallbladder and Common Bile Duct Stones: Cost-Utility and Value-of-Information Analysis

Background: Patients with gallbladder and common bile duct stones are generally treated by pre-operative endoscopic sphincterotomy (ES) followed by laparoscopic cholecystectomy (POES). Recently, a meta-analysis has shown that intra-operative ES during laparoscopic cholecystectomy (IOES) results in fewer complications than POES, with similar efficacy. The cost effectiveness of IOES versus POES is unknown. Objective: The objective of this study was to compare the cost effectiveness of IOES versus POES from the UK NHS perspective. Methods: A decision-tree model estimating and comparing costs to the UK NHS and QALYs gained following a policy of either IOES or POES was developed with a time horizon of 3 years. Uncertainty was investigated with probabilistic sensitivity analysis, and the expected value of perfect information (EVPI) and partial information (EVPPI) were also calculated. Results: IOES was less costly than POES (approximately -£623 per patient [year 2008 values]) and resulted in similar quality of life (+0.008 QALYs per patient) as POES. Given a willingness-to-pay threshold of £20 000 per QALY gained, there was a 92.9% probability that IOES is cost effective compared with POES. Full implementation of IOES could save the NHS £2.8 million per annum. At a willingness to pay of £20 000 per QALY gained, the 10-year population EVPI was estimated at £0.6 million. Conclusions: IOES appears to be cost effective compared with POES.