Objective:To investigate the application value of different metal stents place-ment position in endoscopic drainage of malignant hilar bile duct obstruction.Methods:The retro-spective cohort study was conducted. The clinicopathological data of 300 patients with malignant hilar bile duct obstruction who were admitted to 3 medical centers, including 216 patients in the Third Affiliated Hospital of Naval Medical University, 48 patients in the Xijing Hospital of Air Force Medical University, 36 patients in the First People's Hospital Affiliated to Shanghai Jiaotong University School of Medicine, from January 2012 to January 2019 were collected. There were 164 males and 136 females, aged (67±12)years. All patients were determined to be unresectable by multidisciplinary consultation and underwent endoscopic retrograde cholangiopancreatography. Observation indicators: (1) clinicopathological features of patients; (2) follow-up; (3) analysis of influencing factors for patency time of metal biliary stents and overall survival time of patients. Follow-up was conducted using outpatient examination and telephone interview to detect patency of metal biliary stents and survival of patients up to July 2019 or death of patients. Measurement data with normal distribution were represented as Mean± SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M( Q1, Q3), and comparison between groups was conducted using the Mann-Whitney U test. Count data were expressed as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test or Fisher exact probability. Comparison of ordinal data was conducted using the rank sum test. Kaplan-Meier method was used to calculate survival rates and draw survival curves, and Log-Rank test was used to conduct survival analysis. COX regression model was used for univariate and multivariate analyses. Factors with P<0.1 in univariate analysis were included in multivariate analysis. Results:(1) Clinicopathological features of patients. Of the 300 patients, 163 cases underwent endoscopic drainage with at least one metal biliary stent' distal portion crossing the duodenal main papilla (hereinafter referred to as crossing papilla), and 137 cases underwent endoscopic drainage with no metal biliary stent' distal portion crossing the duodenal main papilla (hereinafter referred to as no crossing papilla). Age, disease type (hilar cholangiocarcinoma, hepatocellular carcinoma, intrahepatic cholangio-carcinoma, gallbladder carcinoma, metastatic cholangiocarcinoma), metal biliary stents type (unilateral metal biliary stent, bilateral metal biliary stents) of patients with crossing papilla were (68±13)years, 95, 8, 11, 31, 18, 63, 100, respectively. The above indicators of patients with no crossing papilla were (64±12)years, 63, 22, 20, 23, 9, 126, 11, respectively. There were significant differences in the above indicators between patients with crossing papilla and patients with no crossing papilla ( t=2.70, χ2=17.69, 90.79, P<0.05). (2) Follow-up. All the 300 patients were followed up for 5.4(3.1,9.3)months. The patency time of metal biliary stents was 9.0(8.2,9.8)months and 6.4(4.8,8.0)months of patients with crossing papilla and patients with no crossing papilla, showing a significant difference between them ( χ2=8.23, P<0.05). The overall survival time was 5.5(4.2,6.8)months and 5.5(4.3,6.8)months of patients with crossing papilla and patients with no crossing papilla, showing no significant difference between them ( χ2=0.28, P>0.05). (3) Analysis of influencing factors for patency time of metal biliary stents and overall survival time of patients. Results of univariate analysis showed that type of metal biliary stents and the placement position of metal biliary stents were related factors affecting the patency time of metal biliary stents [ hazard ratio( HR)=0.44, 0.60, 95% confidence intervals as 0.30?0.64, 0.42?0.85, P<0.05]. Results of multi-variate analysis showed that bilateral metal biliary stents was an independent protective factor for the patency time of metal biliary stents ( HR=0.46, 95% confidence interval as 0.29?0.72, P<0.05). Results of univariate analysis showed that disease type (intrahepatic cholangiocarcinoma versus hilar cholangiocarcinoma), preoperative serum total bilirubin, type of metal biliary stents, anti-tumor therapy were related factors affecting the overall survival time of patients ( HR=1.05, 1.43, 0.72, 0.61, 95% confidence intervals as 0.70?1.57, 1.12?1.83, 0.55?0.92, 0.47?0.81, P<0.05). Results of multi-variate analysis showed that age >60 years, disease type as hepatocellular carcinoma, preoperative serum total bilirubin >200 μmol/L were independent risk factors for the overall survival time of patients ( HR=1.35, 1.98, 1.46, 95% confidence intervals as 1.02?1.79, 1.40?2.80, 1.13?1.89, P<0.05), and bilateral metal biliary stents, anti-tumor therapy were independent protective factors for the overall survival time of patients ( HR=0.68, 0.60, 95% confidence intervals as 0.53?0.89, 0.45?0.80, P<0.05). Conclusions:Endoscopic drainage with or without metal biliary stents' distal portion crossing the duodenal main papilla is safe and feasible for patients with malignant hilar bile duct obstruction. Bilateral metal biliary stents is an independent protective factor for the patency time of metal biliary stents. Age >60 years, disease type as hepatocellular carcinoma, preoperative serum total bilirubin >200 μmol/L are independent risk factors for the overall survival time of patients, and bilateral metal biliary stents, anti-tumor therapy are independent protective factors for the overall survival time of patients.