Biliary metal stents should be placed near the hilar duct in distal malignant biliary stricture patients

Table 3 Risk factors for self-expandable metallic stent dysfunction

	Univariate analysis			Multivariate analysis
	Hazard ratio	95%CI	P value	Hazard ratio	95%CI	P value
Lower group	11.42	2.61–49.83	< 0.01	9.94	2.25–44.0	< 0.01
Age	1.04	0.997–1.09	0.07
Sex, male	0.88	0.35–2.2	0.8
ALT	1.003	1.001–1.01	< 0.01	1.002	1.0–1.004	0.07
TB	1.05	0.99–1.12	0.1
Cause of stricture, pancreaticobiliary	0.41	0.09–1.9	0.26
Chemotherapy	0.89	0.34–2.31	0.81
Duodenal stricture	1.27	0.42–3.83	0.67
CBD above diameter stricture	1.06	0.94–1.19	0.35
CBD stricture diameter	1.004	0.56–1.79	0.99
CBD stricture length	0.99	0.69–1.41	0.95
Year (2011–2015)	1.35	0.55-3.32	0.52
Use of CSEMS	0.67	0.28–1.62	0.37
Use of covered WallFlex stent	0.4	0.12–1.36	0.14
Use of covered X Suit NIR usage stent	3.20	0.92–11.14	0.07
SEMS shortening	1.28	0.17–9.73	0.81
Observational period	0.98	0.92–1.04	0.43

SEMS: Self-expandable metallic stent; ALT: Alanine transaminase; TB: Total bilirubin; CBD: Common bile duct; CSEMS: Covered SEMS; CI: Confidence interval.