The roles of magnetic resonance and endoscopic retrograde cholangiopancreatography (MRCP and ERCP) in the diagnosis of patients with suspected sclerosing cholangitis: a cost-effectiveness analysis

Abstract

The optimal approach for diagnosing sclerosing cholangitis remains unclear in the face of competing imaging technologies. We aimed to determine the most cost-effective strategy. A decision model compared three approaches in the work-up of patients with suspected sclerosing cholangitis; all included an initial test, with, if unsuccessful, performance of a second cholangiographic method. They were magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP), termed "MRCP_ERCP", ERCP and MRCP ("ERCP_MRCP"), or ERCP and a repeat ERCP ("ERCP_ERCP"). The implications of true and false positive and negative results with regard to costs and procedural complications were considered, including that of a liver biopsy, if indicated as a result of a negative work-up in the face of persistent clinical suspicion. The unit of effectiveness adopted was that of a correct diagnosis. Probability assumptions were derived from published literature, while cost estimates were derived from time-motion microanalyses or a national database, and expressed in Canadian dollars at 2004 values. Sensitivity analyses, including clinically relevant threshold analyses, were carried out. The average cost-effectiveness ratios were $414 for MRCP_ERCP, $1101 for ERCP_MRCP and $1123 for ERCP_ERCP, per correct diagnosis. The ERCP_MRCP strategy was dominated (more expensive and less effective) by MRCP_ERCP, while ERCP_ERCP was more effective and more costly than MRCP_ERCP, at $289,292 per additional correct diagnosis. Sensitivity and threshold analyses confirmed the robustness of these findings. Based on the model assumptions, a strategy of initial MRCP, followed, if negative, by ERCP is currently the most cost-effective approach to the work-up of patients with suspected sclerosing cholangitis.