If common factors jointly affect country stock markets, it is an indica- tion of global stock market integration. Common factors may affect some markets more/less than other markets, an indication of the degree of glo...If common factors jointly affect country stock markets, it is an indica- tion of global stock market integration. Common factors may affect some markets more/less than other markets, an indication of the degree of global stock market in- tegration/segmentation. In this paper, we study the integration of global stock mar- kets based on the returns on exchange traded funds （ETFs） for the US, Canada, UK, Germany, France, Italy, Australia and Japan. The relationship between country ETF returns and common risk factors may be time-varying across countries, and that favors a regime switching （RS） factor model for the dynamics of the country ETF returns. A RS factor model for the relationship between country ETF returns and common risk factors is fitted to daily data for the period from May 31, 2000 to March 31, 2014. We use the data to test a hierarchy of hypotheses on country ETF returns： （1） common factor exposure across all country ETFs and all regimes; （2） common factor exposure across some country ETFs and all regimes, and （3） common factor exposure across some country ETFs and some regimes. The RS factor model for ETF returns fits the data well and the common factors have variable effects across countries and over regimes展开更多
BACKGROUND Previous studies have revealed that patients with asymptomatic common bile duct(CBD)stones are at a high risk of developing post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP).However...BACKGROUND Previous studies have revealed that patients with asymptomatic common bile duct(CBD)stones are at a high risk of developing post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP).However,no studies to date have addressed the risk factors for PEP in patients with asymptomatic CBD stones.AIM To examine the risk factors for PEP in patients with asymptomatic CBD stones.METHODS Using medical records of three institutions in Japan for 6 years,we identified a total of 1135 patients with choledocholithiasis including 967 symptomatic patients and 168 asymptomatic patients with native papilla who underwent therapeutic ERCP.We performed univariate and multivariate analyses to examine the risk factors for PEP in the 168 patients with asymptomatic CBD stones.RESULTS The overall incidence rate of PEP in all the patients with during study period was 4.7%(53/1135).Of the 168 patients with asymptomatic CBD stones,24(14.3%)developed PEP.In univariate analysis,precut sphincterotomy(P=0.009)and biliary balloon sphincter dilation(P=0.043)were significant risk factors for PEP.In multivariate analysis,precut sphincterotomy(P=0.002,95%CI:2.2-27.8,odds ratio=7.7),biliary balloon sphincter dilation(P=0.015,95%CI:1.4-17.3,odds ratio=4.9),and trainee endoscopists(P=0.048,95%CI:1.01-8.1,odds ratio=2.9)were significant risk factors for PEP.CONCLUSION ERCP for asymptomatic CBD stones should be performed by experienced endoscopists.When performing precut sphincterotomy or biliary balloon sphincter dilation in patients with asymptomatic CBD stones,the placement of a prophylactic pancreatic stent is strongly recommended to prevent PEP.展开更多
BACKGROUND Post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis(PEP)is a critical and poorly managed complication of ERCP. Endoscopists need to understand the risk factors for PEP. However, the major...BACKGROUND Post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis(PEP)is a critical and poorly managed complication of ERCP. Endoscopists need to understand the risk factors for PEP. However, the majority of studies investigating ERCP-related risk factors have included well-trained endoscopists,with the issue of endoscopist experience on PEP incidence not having been systematically evaluated.AIM To explore the risk factors for PEP in beginner endoscopists without supervision.METHODS We performed a retrospective analysis of 293 patients, with na?ve papilla and no history of pancreatitis, treated using bile duct cannulation. Patients were classified according to the endoscopist’s experience(beginner vs expert). The angle of the distal common bile duct(CBD) was measured as the angle between the lower wall of the bile duct and a vertical line extending to the lower wall of the bile duct on coronal view computed tomography.RESULTS After propensity matching, there were no differences between patients treated by the expert and beginner endoscopist with regard to age, sex, mean bile duct dilatation, and ratio of benign disease. The distal CBD angle was classified as acute(> 30o) or obtuse(≤ 30o), based on the mean angle of 29.9o for the group. An acute distal CBD angle was a significant risk factor for PEP for beginner(P =0.049), but not expert.CONCLUSION For beginner endoscopists first performing unsupervised ERCP, cases with an obtuse distal CBD angle may be more appropriate to lower the risk of PEP.展开更多
BACKGROUND Endoscopic sphincterotomy(EST) for the management of common bile duct stones(CBDS) is used increasingly widely because it is a minimally invasive procedure. However, some clinical practitioners argued that ...BACKGROUND Endoscopic sphincterotomy(EST) for the management of common bile duct stones(CBDS) is used increasingly widely because it is a minimally invasive procedure. However, some clinical practitioners argued that EST may be complicated by post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP) and accompanied by a higher recurrence of CBDS than open choledochotomy(OCT). Whether any differences in outcomes exist between these two approaches for treating CBDS has not been thoroughly elucidated to date.AIM To compare the outcomes of EST vs OCT for the management of CBDS and to clarify the risk factors associated with stone recurrence.METHODS Patients who underwent EST or OCT for CBDS between January 2010 and December 2012 were enrolled in this retrospective study. Follow-up data were obtained through telephone or by searching the medical records. Statistical analysis was carried out for 302 patients who had a follow-up period of at least 5 years or had a recurrence. Propensity score matching(1:1) was performed to adjust for clinical differences. A logistic regression model was used to identify potential risk factors for recurrence, and a receiver operating characteristic(ROC)curve was generated for qualifying independent risk factors.RESULTS In total, 302 patients undergoing successful EST(n = 168) or OCT(n = 134) were enrolled in the study and were followed for a median of 6.3 years. After propensity score matching, 176 patients remained, and all covariates were balanced. EST was associated with significantly shorter time to relieving biliary obstruction, anesthetic duration, procedure time, and hospital stay than OCT(P <0.001). The number of complete stone clearance sessions increased significantly in the EST group(P = 0.009). The overall incidence of complications and mortality did not differ significantly between the two groups. Recurrent CBDS occurred in18.8%(33/176) of the patients overall, but no difference was found between the EST(20.5%, 18/88) and OCT(17.0%, 15/88) groups. Factors associated with CBDS recurrence included common bile duct(CBD) diameter > 15 mm(OR =2.72; 95%CI: 1.26-5.87; P = 0.011), multiple CBDS(OR = 5.09; 95%CI: 2.58-10.07; P< 0.001), and distal CBD angle ≤ 145°(OR = 2.92; 95%CI: 1.54-5.55; P = 0.001). The prediction model incorporating these factors demonstrated an area under the receiver operating characteristic curve of 0.81(95%CI: 0.76-0.87).CONCLUSION EST is superior to OCT with regard to time to biliary obstruction relief, anesthetic duration, procedure time, and hospital stay and is not associated with an increased recurrence rate or mortality compared with OCT in the management of CBDS.展开更多
文摘If common factors jointly affect country stock markets, it is an indica- tion of global stock market integration. Common factors may affect some markets more/less than other markets, an indication of the degree of global stock market in- tegration/segmentation. In this paper, we study the integration of global stock mar- kets based on the returns on exchange traded funds （ETFs） for the US, Canada, UK, Germany, France, Italy, Australia and Japan. The relationship between country ETF returns and common risk factors may be time-varying across countries, and that favors a regime switching （RS） factor model for the dynamics of the country ETF returns. A RS factor model for the relationship between country ETF returns and common risk factors is fitted to daily data for the period from May 31, 2000 to March 31, 2014. We use the data to test a hierarchy of hypotheses on country ETF returns： （1） common factor exposure across all country ETFs and all regimes; （2） common factor exposure across some country ETFs and all regimes, and （3） common factor exposure across some country ETFs and some regimes. The RS factor model for ETF returns fits the data well and the common factors have variable effects across countries and over regimes
文摘BACKGROUND Previous studies have revealed that patients with asymptomatic common bile duct(CBD)stones are at a high risk of developing post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP).However,no studies to date have addressed the risk factors for PEP in patients with asymptomatic CBD stones.AIM To examine the risk factors for PEP in patients with asymptomatic CBD stones.METHODS Using medical records of three institutions in Japan for 6 years,we identified a total of 1135 patients with choledocholithiasis including 967 symptomatic patients and 168 asymptomatic patients with native papilla who underwent therapeutic ERCP.We performed univariate and multivariate analyses to examine the risk factors for PEP in the 168 patients with asymptomatic CBD stones.RESULTS The overall incidence rate of PEP in all the patients with during study period was 4.7%(53/1135).Of the 168 patients with asymptomatic CBD stones,24(14.3%)developed PEP.In univariate analysis,precut sphincterotomy(P=0.009)and biliary balloon sphincter dilation(P=0.043)were significant risk factors for PEP.In multivariate analysis,precut sphincterotomy(P=0.002,95%CI:2.2-27.8,odds ratio=7.7),biliary balloon sphincter dilation(P=0.015,95%CI:1.4-17.3,odds ratio=4.9),and trainee endoscopists(P=0.048,95%CI:1.01-8.1,odds ratio=2.9)were significant risk factors for PEP.CONCLUSION ERCP for asymptomatic CBD stones should be performed by experienced endoscopists.When performing precut sphincterotomy or biliary balloon sphincter dilation in patients with asymptomatic CBD stones,the placement of a prophylactic pancreatic stent is strongly recommended to prevent PEP.
基金Supported by Biomedical Research Institute Grant,No.2019B021,Pusan National University Hospital
文摘BACKGROUND Post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis(PEP)is a critical and poorly managed complication of ERCP. Endoscopists need to understand the risk factors for PEP. However, the majority of studies investigating ERCP-related risk factors have included well-trained endoscopists,with the issue of endoscopist experience on PEP incidence not having been systematically evaluated.AIM To explore the risk factors for PEP in beginner endoscopists without supervision.METHODS We performed a retrospective analysis of 293 patients, with na?ve papilla and no history of pancreatitis, treated using bile duct cannulation. Patients were classified according to the endoscopist’s experience(beginner vs expert). The angle of the distal common bile duct(CBD) was measured as the angle between the lower wall of the bile duct and a vertical line extending to the lower wall of the bile duct on coronal view computed tomography.RESULTS After propensity matching, there were no differences between patients treated by the expert and beginner endoscopist with regard to age, sex, mean bile duct dilatation, and ratio of benign disease. The distal CBD angle was classified as acute(> 30o) or obtuse(≤ 30o), based on the mean angle of 29.9o for the group. An acute distal CBD angle was a significant risk factor for PEP for beginner(P =0.049), but not expert.CONCLUSION For beginner endoscopists first performing unsupervised ERCP, cases with an obtuse distal CBD angle may be more appropriate to lower the risk of PEP.
文摘BACKGROUND Endoscopic sphincterotomy(EST) for the management of common bile duct stones(CBDS) is used increasingly widely because it is a minimally invasive procedure. However, some clinical practitioners argued that EST may be complicated by post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP) and accompanied by a higher recurrence of CBDS than open choledochotomy(OCT). Whether any differences in outcomes exist between these two approaches for treating CBDS has not been thoroughly elucidated to date.AIM To compare the outcomes of EST vs OCT for the management of CBDS and to clarify the risk factors associated with stone recurrence.METHODS Patients who underwent EST or OCT for CBDS between January 2010 and December 2012 were enrolled in this retrospective study. Follow-up data were obtained through telephone or by searching the medical records. Statistical analysis was carried out for 302 patients who had a follow-up period of at least 5 years or had a recurrence. Propensity score matching(1:1) was performed to adjust for clinical differences. A logistic regression model was used to identify potential risk factors for recurrence, and a receiver operating characteristic(ROC)curve was generated for qualifying independent risk factors.RESULTS In total, 302 patients undergoing successful EST(n = 168) or OCT(n = 134) were enrolled in the study and were followed for a median of 6.3 years. After propensity score matching, 176 patients remained, and all covariates were balanced. EST was associated with significantly shorter time to relieving biliary obstruction, anesthetic duration, procedure time, and hospital stay than OCT(P <0.001). The number of complete stone clearance sessions increased significantly in the EST group(P = 0.009). The overall incidence of complications and mortality did not differ significantly between the two groups. Recurrent CBDS occurred in18.8%(33/176) of the patients overall, but no difference was found between the EST(20.5%, 18/88) and OCT(17.0%, 15/88) groups. Factors associated with CBDS recurrence included common bile duct(CBD) diameter > 15 mm(OR =2.72; 95%CI: 1.26-5.87; P = 0.011), multiple CBDS(OR = 5.09; 95%CI: 2.58-10.07; P< 0.001), and distal CBD angle ≤ 145°(OR = 2.92; 95%CI: 1.54-5.55; P = 0.001). The prediction model incorporating these factors demonstrated an area under the receiver operating characteristic curve of 0.81(95%CI: 0.76-0.87).CONCLUSION EST is superior to OCT with regard to time to biliary obstruction relief, anesthetic duration, procedure time, and hospital stay and is not associated with an increased recurrence rate or mortality compared with OCT in the management of CBDS.
