Partially covered metal stents have longer patency than uncovered and fully covered metal stents in the management of distal malignant biliary obstruction: a retrospective study

Table 3 Univariate and multivariate analyses of risk factors for recurrent biliary obstruction

			Stent dysfunction (n = 44)	univariate			multivariate
		n		HR	95% CI	P value	HR	95% CI	P value
Type of stent	Uncovered	44	20			1
	Partially	28	8	0.33	0.14–0.79	0.012*	0.30	0.11–0.77	0.013*
	Fully	29	16	0.96	0.49–1.85	0.892	0.92	0.43–1.95	0.822
Age	<75	48	20			1
Age	≥75	53	24	1.25	0.68–2.30	0.464
Sex	male	41	23			1
Sex	female	60	21	1.54	0.84–2.80	0.162	1.50	0.75–3.03	0.256
Performance status	0–2	93	41			1
Performance status	3,4	8	3	3.14	0.93–10.60	0.066	4.91	1.13–21.40	0.034*
Primary malignancy	others	21	3			1
Primary malignancy	pancreatic	80	41	2.89	0.89–9.35	0.077	3.76	1.10–12.87	0.035*
location of stricture	lower	76	34			1
location of stricture	middle	25	10	0.64	0.31–1.35	0.241
Length of stricture	≤20 mm	53	20			1
Length of stricture	>20 mm	48	24	1.61	0.88–2.95	0.120	1.33	0.69–2.54	0.395
Stent length	≤6 cm	88	39			1
Stent length	8 cm	13	5	2.24	0.87–5.77	0.095	2.16	0.73–6.38	0.165
Length of a portion of the stent over the stricture	<30 mm	49	23			1
Length of a portion of the stent over the stricture	≥30 mm	52	21	1.09	0.59–1.99	0.787
Prior transpapillary Drainage	No	41	15			1
Prior transpapillary Drainage	Yes	60	29	0.72	0.38–1.36	0.310
History of cholecystectomy	No	94	43			1
History of cholecystectomy	Yes	7	1	0.62	0.08–4.53	0.638
EST	No	14	7			1
EST	Yes	87	37	0.72	0.30–1.72	0.464
duodenal invasion	absent	67	22			1
duodenal invasion	present	34	22	1.68	0.92–3.06	0.091	1.62	0.81–3.25	0.172
Duodenal stent	absent	85	35			1
Duodenal stent	Present	16	9	1.29	0.60–2.79	0.518
Chemotherapy	No	30	9			1
Chemotherapy	Yes	71	35	0.55	0.26–1.17	0.120	0.47	0.19–1.15	0.098