Table 4.

Effect of Single-stage Endoscopic Stone Removal on Complications after Controlling for Confounding Factors.

	Odds ratio	p value/(95% CI)
Single-stage endoscopic stone removal	1.4	0.52 / (0.52-3.5)
Propensity score group1‡		0.010
Propensity score group2§		0.16
Propensity score group3**		0.69

CI: confidence interval

^‡Risk factors that were associated with both complications and single-stage endoscopic stone removal in univariate analysis: indication for ERCP, time of deep cannulation, serum bilirubin, biliary stent placement, and antibiotics were included.

^§Procedure-related risk factors associated with complications in previous studies: endoscopist’s experience, sphincterotomy technique, pancreatic injection, chemoprevention, and pancreatic stent placement were included.

**Patient-related risk factors associated with complications in previous studies: age, sex, coexisting illness, antithrombotic drug, diameter of common bile duct, stone size, stone number, gallstones, and gallbladder were included.