HPB
http://dx.doi.org/10.1016/j.hpb.2016.05.008
ORIGINAL ARTICLE
Early surgical bypass versus endoscopic stent placement in pancreatic cancer Lindsay A. Bliss, Mariam F. Eskander, Tara S. Kent, Ammara A. Watkins, Susanna W.L. de Geus, Alessandra Storino, Sing Chau Ng, Mark P. Callery, A. James Moser & Jennifer F. Tseng Surgical Outcomes Analysis & Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
Abstract Introduction: The optimal treatment for biliary obstruction in pancreatic cancer remains controversial between surgical bypass and endoscopic stenting. Methods: Retrospective analysis of unresected pancreatic cancer patients in the Healthcare Cost and Utilization Project Florida State Inpatient and Ambulatory Surgery databases (2007–2011). Propensity score matching by procedure. Primary outcome was reintervention, and secondary outcomes were readmission, overall length of stay (LOS), discharge home, death and cost. Multivariate analyses performed by logistic regression. Results: In a matched cohort of 622, 20.3% (63) of endoscopic and 4.5% (14) of surgical patients underwent reintervention (p < 0.0001) and 56.0% (174) vs. 60.1% (187) were readmitted (p = 0.2909). Endoscopic patients had lower median LOS (10 vs. 19 days, p < 0.0001) and cost ($21,648 vs. $38,106, p < 0.0001) as well as increased discharge home (p = 0.0029). No difference in mortality on index admission. On multivariate analysis, initial procedure not predictive of readmission (p = 0.1406), but early surgical bypass associated with lower odds of reintervention (OR = 0.233, 95% CI 0.119, 0.434). Discussion: Among propensity score-matched patients receiving bypass vs. stenting, readmission and mortality rates are similar. However, candidates for both techniques may experience fewer subsequent procedures if offered early biliary bypass with the caveats of decreased discharge home and increased cost/LOS. Received 10 December 2015; accepted 13 May 2016
Correspondence Jennifer F. Tseng, Division of Surgical Oncology, BIDMC Cancer Center, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Stoneman 9, Boston, MA 02215, United States. Tel: +1 617 667 3746. Fax: +1 617 667 2792. E-mail: [email protected]
Introduction In the 80% of patients diagnosed with advanced, unresectable pancreatic cancer, biliary obstruction is common.1 Options for management include surgical biliary bypass or endoscopic stenting. Endoscopic stenting has several advantages: it can be performed on an outpatient basis, without general anesthesia or abdominal incisions, and is less invasive than surgery. However, stents can become occluded resulting in cholangitis or
Presented in part at the 2015 American Society of Clinical Oncology and
pancreatitis, they can migrate and erode through surrounding structures, and they may require exchange or replacement.2 The literature comparing early surgical bypass to endoscopic stenting is outdated and inconsistent, and the optimal technique for relief of obstructive jaundice remains controversial. In this study, we compared post-procedural outcomes between unresected pancreatic cancer patients equally likely to undergo early surgical bypass and endoscopic biliary stenting, focusing on the need for reintervention. We hypothesized that while reintervention would be more common in the stent group, a higher rate of death, inpatient readmission and cost would be associated with biliary bypass.
Society of Surgical Oncology annual meetings.
HPB 2016, 18, 671–677
© 2016 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.
HPB
672
Methods Design We performed a retrospective review of Healthcare Cost and Utilization Project (HCUP) Florida State Inpatient Database (SID) and State Ambulatory Surgery and Services Database (SASD). Both databases are all-payer administrative database assembled by the HCUP, part of the Agency for Healthcare Research and Quality (AHRQ).3 The SID includes discharge data from inpatient discharges from acute care hospitals, and the SASD includes data from ambulatory encounters where an invasive procedure was performed. The databases include patient and facility characteristics for each encounter. Diagnosis and procedure data is available as ICD-9 procedure and diagnosis codes as well as CPT codes. A unique HCUP visitlink variable is assigned to each patient to allow individual patients to be followed across time and at multiple institutions. Patients with pancreatic cancer and age 18 years or older during 2007–2011 were identified using query of ICD-9 diagnosis codes (157). Any inpatient or ambulatory endoscopic biliary stents or surgical biliary bypasses were identified using ICD-9 procedure codes and CPT codes. Procedure codes for endoscopic biliary included endoscopic insertion of or exchange of a stent in the pancreatic or bile ducts (ICD-9 codes: 51.87, 52.93; CPT codes: 43267, 43268, 43269, 43274, 43276, 47556, 47801). Procedure codes for surgical biliary bypass included choledochoenterostomy, cholecystenterostomy and anastomosis of the hepatic duct to the gastrointestinal tract (ICD-9 codes: 51.36, 51.37, 51.39; CPT codes: 47570, 47612, 47701, 47720, 47721, 47740, 47741, 47760, 47765, 47780, 47785). In order to identify those biliary bypass patients who had a concurrent gastrojejunostomy performed (a “double bypass”), ICD-9 code 44.39 and CPT codes 43820, 43825, and 48547 were used. The Visitlink variable was used to examine all inpatient and ambulatory visits for each individual patient across time. Patients were divided into two groups based on the first biliary decompression procedure: endoscopic stent placement or early surgical biliary bypass. Those with a surgical bypass performed within 30 days of initial endoscopic stent placement were classified as early surgical bypass patients because the decision to proceed to surgery was likely to offer definitive management (replacing a temporary plastic stent, for example), rather than to address an early stent failure. Patients with an inpatient pancreatic resection at any time during the study period were identified by ICD-9 code (52.5, 52.6, 52.7) and excluded from analysis. Propensity score matching Patient demographic were collected from the discharge record—inpatient or ambulatory—associated with the index procedure. These included sex, age, median ZIP code income, insurance type, and race. Patients with missing characteristics for the index procedure were removed from the analysis. The extent
HPB 2016, 18, 671–677
of comorbid conditions was calculated using an Elixhauser score, generated using the HCUP Comorbidity Software, Version 3.7.4 This system was specifically designed for use in large administrative datasets and identifies comorbidities using ICD-9 codes and Diagnosis-Related Groups. The year and urgency of the index procedure was also identified. Due to concerns that many patients in the initial stent population would not be candidates for surgical bypass, the decision was made a priori to create a propensity score matched cohort in order to analyze patients with similar likelihoods of undergoing endoscopic stent placement and surgical bypass. A logistic regression model was created to predict likelihood of undergoing surgical bypass. Covariates included in the model were year of index procedure, urgency of index procedure, sex, race (dichotomized into white and non-white), age (dichotomized into less than 65 and 65 or greater), Elixhauser comorbidity score (dichotomized into 0–1 and 2 or greater), median ZIP income (dichotomized into upper and lower halves), and primary payer (grouped into Medicare, Medicaid, private, and other or none). We matched using a 1:1, optimal, nearest neighbor matching with calipers and without replacement. Calipers were set at 0.2 of the standard deviation of the distribution of the propensity score. This matching strategy and caliper range will eliminate 99% of the bias among the measured confounders.5 Patient outcomes The primary outcome was subsequent intervention for management of biliary obstruction at any point after the initial intervention. This was broken down into endoscopic stent replacement or exchange, surgical biliary bypass, or percutaneous procedures facilitating biliary drainage (ICD-9 codes: 51.01, 51.96, 51.98, 51.99; CPT codes: 47490, 47510, 47511, 47552, 47553, 47554, 47555, 47556, 47630). Secondary outcomes include inpatient readmission at least once after the initial procedure, length of stay (LOS) at the time of the index procedure, discharge to home at the time of the index procedure, death during index admission, total LOS during the study period and total cost of care during the study period. A sensitivity analysis for LOS was performed among patients receiving a biliary bypass with a concurrent gastrojejunostomy. The first revisit (whether inpatient or ambulatory) was queried to identify patients with obstructive complications—cholangitis (ICD-9 code: 576.1), evidence of biliary obstruction (ICD-9 code: 576.2, 782.4), or acute pancreatitis (ICD-9 code: 577.0). Cost of care was determined using charge data for each inpatient and ambulatory encounter. Charge information available does not reflect the true cost of services or the reimbursement. To approximate costs by converting billed charge we used the supplemental SID HCUP Cost-to-Charge Ratio files.6 Based on all-payer inpatient costs for each hospital as reported to the Centers for Medicare and Medicaid Services (CMS), these files contain hospital-specific cost-to-charge ratios.
© 2016 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.
HPB
673
Statistical analysis Patient characteristics, dichotomized or categorized to enhance clinical relevance, were compared between the initial endoscopic stent and the early surgical bypass groups using chi-square. These analyses were performed on the unmatched and propensity score matched cohorts. For patient outcomes, chi-square test was used to evaluate binary outcome variables for the propensity matched cohort. Continuous outcome variables—LOS, cost, and number of readmissions—were assumed to be non-normal. Median values and interquartile ranges (IQRs) were calculated for the early surgical bypass and initial endoscopic stent groups. Comparisons were performed using the Wilcoxon rank sum test. Univariate logistic regression modeling of likelihood of subsequent procedure and inpatient readmission were performed for the propensity score matched cohort. Multivariate logistic regression models predicting subsequent procedure and readmission were created using all available patient characteristics as well as the procedure group—initial endoscopic stent or early surgical bypass—and index procedure characteristics, including length of stay, urgency, and year of procedure. For all regression modeling, Firth’s penalized maximum likelihood for rare events was utilized.7 Statistical analyses were performed using SAS statistical analysis software, version 9.3/9.4 (SAS Institute Inc., Cary, NC). For all analyses, p value of less 0.05 was considered statistically significant. Cell sizes less than 11 are not reported in compliance with the HCUP data use agreement. This study was approved by the Beth Israel Deaconess Medical Center Institutional Review Board. No authors have conflicts of interest.
Results
Stent
Outcomes before matching Bypassed patients were more likely to have an index length of stay longer than 10 days (62.2% [194] vs. 24.6% [444],
Bypass
p-Value
n
%
n
%
Characteristics
1803
85.2%
312
14.8%
Age 65
1363
75.6%
198
63.5%
http://dx.doi.org/10.1016/j.hpb.2016.05.008
ORIGINAL ARTICLE
Early surgical bypass versus endoscopic stent placement in pancreatic cancer Lindsay A. Bliss, Mariam F. Eskander, Tara S. Kent, Ammara A. Watkins, Susanna W.L. de Geus, Alessandra Storino, Sing Chau Ng, Mark P. Callery, A. James Moser & Jennifer F. Tseng Surgical Outcomes Analysis & Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States
Abstract Introduction: The optimal treatment for biliary obstruction in pancreatic cancer remains controversial between surgical bypass and endoscopic stenting. Methods: Retrospective analysis of unresected pancreatic cancer patients in the Healthcare Cost and Utilization Project Florida State Inpatient and Ambulatory Surgery databases (2007–2011). Propensity score matching by procedure. Primary outcome was reintervention, and secondary outcomes were readmission, overall length of stay (LOS), discharge home, death and cost. Multivariate analyses performed by logistic regression. Results: In a matched cohort of 622, 20.3% (63) of endoscopic and 4.5% (14) of surgical patients underwent reintervention (p < 0.0001) and 56.0% (174) vs. 60.1% (187) were readmitted (p = 0.2909). Endoscopic patients had lower median LOS (10 vs. 19 days, p < 0.0001) and cost ($21,648 vs. $38,106, p < 0.0001) as well as increased discharge home (p = 0.0029). No difference in mortality on index admission. On multivariate analysis, initial procedure not predictive of readmission (p = 0.1406), but early surgical bypass associated with lower odds of reintervention (OR = 0.233, 95% CI 0.119, 0.434). Discussion: Among propensity score-matched patients receiving bypass vs. stenting, readmission and mortality rates are similar. However, candidates for both techniques may experience fewer subsequent procedures if offered early biliary bypass with the caveats of decreased discharge home and increased cost/LOS. Received 10 December 2015; accepted 13 May 2016
Correspondence Jennifer F. Tseng, Division of Surgical Oncology, BIDMC Cancer Center, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Ave, Stoneman 9, Boston, MA 02215, United States. Tel: +1 617 667 3746. Fax: +1 617 667 2792. E-mail: [email protected]
Introduction In the 80% of patients diagnosed with advanced, unresectable pancreatic cancer, biliary obstruction is common.1 Options for management include surgical biliary bypass or endoscopic stenting. Endoscopic stenting has several advantages: it can be performed on an outpatient basis, without general anesthesia or abdominal incisions, and is less invasive than surgery. However, stents can become occluded resulting in cholangitis or
Presented in part at the 2015 American Society of Clinical Oncology and
pancreatitis, they can migrate and erode through surrounding structures, and they may require exchange or replacement.2 The literature comparing early surgical bypass to endoscopic stenting is outdated and inconsistent, and the optimal technique for relief of obstructive jaundice remains controversial. In this study, we compared post-procedural outcomes between unresected pancreatic cancer patients equally likely to undergo early surgical bypass and endoscopic biliary stenting, focusing on the need for reintervention. We hypothesized that while reintervention would be more common in the stent group, a higher rate of death, inpatient readmission and cost would be associated with biliary bypass.
Society of Surgical Oncology annual meetings.
HPB 2016, 18, 671–677
© 2016 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.
HPB
672
Methods Design We performed a retrospective review of Healthcare Cost and Utilization Project (HCUP) Florida State Inpatient Database (SID) and State Ambulatory Surgery and Services Database (SASD). Both databases are all-payer administrative database assembled by the HCUP, part of the Agency for Healthcare Research and Quality (AHRQ).3 The SID includes discharge data from inpatient discharges from acute care hospitals, and the SASD includes data from ambulatory encounters where an invasive procedure was performed. The databases include patient and facility characteristics for each encounter. Diagnosis and procedure data is available as ICD-9 procedure and diagnosis codes as well as CPT codes. A unique HCUP visitlink variable is assigned to each patient to allow individual patients to be followed across time and at multiple institutions. Patients with pancreatic cancer and age 18 years or older during 2007–2011 were identified using query of ICD-9 diagnosis codes (157). Any inpatient or ambulatory endoscopic biliary stents or surgical biliary bypasses were identified using ICD-9 procedure codes and CPT codes. Procedure codes for endoscopic biliary included endoscopic insertion of or exchange of a stent in the pancreatic or bile ducts (ICD-9 codes: 51.87, 52.93; CPT codes: 43267, 43268, 43269, 43274, 43276, 47556, 47801). Procedure codes for surgical biliary bypass included choledochoenterostomy, cholecystenterostomy and anastomosis of the hepatic duct to the gastrointestinal tract (ICD-9 codes: 51.36, 51.37, 51.39; CPT codes: 47570, 47612, 47701, 47720, 47721, 47740, 47741, 47760, 47765, 47780, 47785). In order to identify those biliary bypass patients who had a concurrent gastrojejunostomy performed (a “double bypass”), ICD-9 code 44.39 and CPT codes 43820, 43825, and 48547 were used. The Visitlink variable was used to examine all inpatient and ambulatory visits for each individual patient across time. Patients were divided into two groups based on the first biliary decompression procedure: endoscopic stent placement or early surgical biliary bypass. Those with a surgical bypass performed within 30 days of initial endoscopic stent placement were classified as early surgical bypass patients because the decision to proceed to surgery was likely to offer definitive management (replacing a temporary plastic stent, for example), rather than to address an early stent failure. Patients with an inpatient pancreatic resection at any time during the study period were identified by ICD-9 code (52.5, 52.6, 52.7) and excluded from analysis. Propensity score matching Patient demographic were collected from the discharge record—inpatient or ambulatory—associated with the index procedure. These included sex, age, median ZIP code income, insurance type, and race. Patients with missing characteristics for the index procedure were removed from the analysis. The extent
HPB 2016, 18, 671–677
of comorbid conditions was calculated using an Elixhauser score, generated using the HCUP Comorbidity Software, Version 3.7.4 This system was specifically designed for use in large administrative datasets and identifies comorbidities using ICD-9 codes and Diagnosis-Related Groups. The year and urgency of the index procedure was also identified. Due to concerns that many patients in the initial stent population would not be candidates for surgical bypass, the decision was made a priori to create a propensity score matched cohort in order to analyze patients with similar likelihoods of undergoing endoscopic stent placement and surgical bypass. A logistic regression model was created to predict likelihood of undergoing surgical bypass. Covariates included in the model were year of index procedure, urgency of index procedure, sex, race (dichotomized into white and non-white), age (dichotomized into less than 65 and 65 or greater), Elixhauser comorbidity score (dichotomized into 0–1 and 2 or greater), median ZIP income (dichotomized into upper and lower halves), and primary payer (grouped into Medicare, Medicaid, private, and other or none). We matched using a 1:1, optimal, nearest neighbor matching with calipers and without replacement. Calipers were set at 0.2 of the standard deviation of the distribution of the propensity score. This matching strategy and caliper range will eliminate 99% of the bias among the measured confounders.5 Patient outcomes The primary outcome was subsequent intervention for management of biliary obstruction at any point after the initial intervention. This was broken down into endoscopic stent replacement or exchange, surgical biliary bypass, or percutaneous procedures facilitating biliary drainage (ICD-9 codes: 51.01, 51.96, 51.98, 51.99; CPT codes: 47490, 47510, 47511, 47552, 47553, 47554, 47555, 47556, 47630). Secondary outcomes include inpatient readmission at least once after the initial procedure, length of stay (LOS) at the time of the index procedure, discharge to home at the time of the index procedure, death during index admission, total LOS during the study period and total cost of care during the study period. A sensitivity analysis for LOS was performed among patients receiving a biliary bypass with a concurrent gastrojejunostomy. The first revisit (whether inpatient or ambulatory) was queried to identify patients with obstructive complications—cholangitis (ICD-9 code: 576.1), evidence of biliary obstruction (ICD-9 code: 576.2, 782.4), or acute pancreatitis (ICD-9 code: 577.0). Cost of care was determined using charge data for each inpatient and ambulatory encounter. Charge information available does not reflect the true cost of services or the reimbursement. To approximate costs by converting billed charge we used the supplemental SID HCUP Cost-to-Charge Ratio files.6 Based on all-payer inpatient costs for each hospital as reported to the Centers for Medicare and Medicaid Services (CMS), these files contain hospital-specific cost-to-charge ratios.
© 2016 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.
HPB
673
Statistical analysis Patient characteristics, dichotomized or categorized to enhance clinical relevance, were compared between the initial endoscopic stent and the early surgical bypass groups using chi-square. These analyses were performed on the unmatched and propensity score matched cohorts. For patient outcomes, chi-square test was used to evaluate binary outcome variables for the propensity matched cohort. Continuous outcome variables—LOS, cost, and number of readmissions—were assumed to be non-normal. Median values and interquartile ranges (IQRs) were calculated for the early surgical bypass and initial endoscopic stent groups. Comparisons were performed using the Wilcoxon rank sum test. Univariate logistic regression modeling of likelihood of subsequent procedure and inpatient readmission were performed for the propensity score matched cohort. Multivariate logistic regression models predicting subsequent procedure and readmission were created using all available patient characteristics as well as the procedure group—initial endoscopic stent or early surgical bypass—and index procedure characteristics, including length of stay, urgency, and year of procedure. For all regression modeling, Firth’s penalized maximum likelihood for rare events was utilized.7 Statistical analyses were performed using SAS statistical analysis software, version 9.3/9.4 (SAS Institute Inc., Cary, NC). For all analyses, p value of less 0.05 was considered statistically significant. Cell sizes less than 11 are not reported in compliance with the HCUP data use agreement. This study was approved by the Beth Israel Deaconess Medical Center Institutional Review Board. No authors have conflicts of interest.
Results
Stent
Outcomes before matching Bypassed patients were more likely to have an index length of stay longer than 10 days (62.2% [194] vs. 24.6% [444],
Bypass
p-Value
n
%
n
%
Characteristics
1803
85.2%
312
14.8%
Age 65
1363
75.6%
198
63.5%
