Table 3.

Cox proportional hazards analysis with endoscopic retrograde cholangiopancreatography for retained common bile duct stones

	Patients with CBD stones identified by IOC (n = 14 402)	Univariable analysis		Multivariable analysis
		Hazard ratio of retained CBD stones*	P	Hazard ratio of retained CBD stones*	P
CBD stones management
Intervention (reference)	12 971 (90.1)	-	-	-	-
Surveillance	1431 (9.9)	2.8 (2.5, 3.2)	<0.005	5.5 (4.8, 6.4)	<0.005
Diameter of largest CBD stones on IOC
<4 mm (reference)	4116 (28.6)	-	-	-	-
4–8 mm	7939 (55.1)	1.7 (1.5, 2.0)	<0.005	2.3 (1.9, 2.7)	<0.005
>8 mm	2347 (16.3)	4.3 (3.6, 5.0)	<0.005	4.7 (3.9, 5.8)	<0.005
Common bile duct diameter on IOC
<6 mm (reference)	1827 (12.7)	-	-	-	-
6–10 mm	8647 (60)	1.5 (1.2, 1.8)	0.001	1.4 (1.1, 1.8)	0.003
>10 mm	3928 (27.3)	2.9 (2.4, 3.6)	<0.005	2.0 (1.5, 2.5)	<0.005
Position of CBD stones in common bile duct on IOC†
Low CBD stones (reference)	13 212 (91.7)	-	-	-	-
High CBD stones	1190 (8.3)	2.5 (2.1, 2.8)	<0.005	1.9 (1.6, 2.2)	<0.005
Preoperative symptoms of CBD stones‡
No (reference)	6194 (43.0)	-	-	-	-
Yes	8208 (57.0)	1.1 (1.0, 1.3)	0.026	1.0 (0.9, 1.2)	0.839
Emergency cholecystectomy
No (reference)	5990 (41.6)	-	-	-	-
Yes	8412 (58.4)	1.1 (1.0, 1.2)	0.237	1.2 (1.1, 1.4)	0.001
Gender
Female (reference)	9300 (64.6)	-	-	-	-
Male	5102 (35.4)	1.2 (1.1, 1.4)	<0.005	1.1 (1.0, 1.3)	0.042
Age§
Less than cohort median (reference)	6604 (45.9)	-	-	-
Greater than cohort median	7798 (54.1)	1.5 (1.4, 1.7)	<0.005	1.2 (1.1, 1.4)	0.002

Values in parentheses are percentages unless indicated otherwise;

^*values in parentheses are 95 per cent confidence intervals.

^†High common bile duct (CBD) stones are CBD stones located above the cystic duct.

^‡Previous or ongoing jaundice or pancreatitis. §Median age for the entire cohort was 51 years. IOC, intraoperative cholangiography.