The Cost Effectiveness of Endoscopic Ultrasound ( EUS ) Based Strategy in Diagnosis of Common Bile Duct Stones
The Cost Effectiveness of Endoscopic Ultrasound ( EUS ) Based Strategy in Diagnosis of Common Bile Duct Stones
Multiple reports in the literature showed the efficacy of EUS comparable to ERCP in the
 diagnosis of common bile duct ( CBD ) stone. The EUS-based strategy has provided the cost
 effectiveness in diagnosis of CBD stone in defined patient risk groups was showed in previous
 studies. The aim of our study was to assess the cost effectiveness of EUS based strategy
 versus ERCP based strategy in diagnosis of CBD stones in patients with intermediate risks for
 CBD stones in a real working situation in a developing country.
Background: Multiple reports showed the efficacy of EUS comparable to ERCP in the diagnosis
 of CBD stone. The EUS-based strategy has provided the cost saving in diagnosis of CBD stone
 in patients with intermediate risk in previous studies in western population. There were
 multiple parameters involved the cost effectiveness analysis included cost of ERCP, cost of
 EUS, prevalence of CBD stones, the sensitivity and specificity of EUS and the rate of
 complications related to EUS and ERCP. These parameter may vary from center to center and
 from region to region.

 Aims: To assess the cost effectiveness of EUS based strategy versus ERCP based strategy in
 diagnosis of CBD stones in patients with intermediate risk in a developing country.

 Method : A prospective study in 141 patients with suspected CBD stones based on clinical,
 biochemical and imaging by trans-abdominal ultrasonography or computed abdominal tomography.
 All patients underwent EUS. All patients with high risk for CBD stone underwent ERCP after
 the EUS. For patients with intermediate risk for CBD stone, ERCP's were done at the
 discretion of the attending physicians. For patients with ERCP done, the diagnosis of CBD
 stone was confirmed by ERCP demonstration of CBD stone. In patients with intermediate risk
 without ERCP done, clinical follow up to assess biliary symptoms and liver function test as
 surrogated markers for CBD stone at 3 months interval for one year were done. The false
 negative rate in patients with EUS and ERCP done in this study was used to estimate the false
 negative rate in patients in clinical surrogated group.

 Definition: High risk of CBD stones was defined when CBD stone was detected by US/CT or
 dilated duct with abnormal liver function test ( LFT ). Intermediate risk of CBD stones was
 defined when US/CT showed normal bile duct with abnormal LFT or dilated duct with normal LFT.

 Cost analysis :The cost of making diagnosis of CBD stone excluding all costs of treatment was
 analyzed. The cost of all patients with suspected CBD stones undergoing ERCP was calculated
 and compared with the strategy of EUS follow by ERCP. The cost was evaluated by (1) mean
 costs of EUS and ERCP based on the actual cost in our center which included costs of medical
 staffs, disposable materials, drugs, equipment amortization and maintenance. (2) cost
 associated with complications induced by the procedure.

 Statistical analysis: Test performance of the endoscopic ultrasound in diagnosis of CBD
 stones was analyzed with two by two tables. The sensitivity, specificity, positive and
 negative predictive values were calculated.
Inclusion Criteria:

 -  history of biliary pain or recent cholangitis

 -  acute pancreatitis

 -  abnormal liver function test

 -  dilatation of CBD and or CBD stone detected by trans-abdominal ultrasound and or
 computed tomography.

 Exclusion Criteria:

 -  unstable hemodynamics

 -  severe coagulopathy

 -  refusal to participate