j o u r n a l o f s u r g i c a l r e s e a r c h x x x ( 2 0 1 4 ) 1 e7
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.JournalofSurgicalResearch.com
Inpatient survival after gastrectomy for gastric cancer in the 21st century Han Wang, MD, MPH, Timothy M. Pawlik, MD, MPH, PhD, Mark D. Duncan, MD, Xuan Hui, MD, ScM, Shalini Selvarajah, MD, MPH, Joseph K. Canner, MHS, Adil H. Haider, MD, MPH, Nita Ahuja, MD, and Eric B. Schneider, PhD* Department of Surgery, Center for Surgical Trials and Outcomes Research, Johns Hopkins School of Medicine, Baltimore, Maryland
article info
abstract
Article history:
Background: Surgical treatment for gastric cancer has evolved substantially. To understand
Received 4 January 2014
how changes in patient- and hospital-level factors are associated with outcomes over the
Received in revised form
last decade, we examined a nationally representative sample.
26 February 2014
Methods: Retrospective cross-sectional discharge data from the 2001e2010 Nationwide Inpa-
Accepted 5 March 2014
tient Sample were analyzed using cross tabulation and multivariable regression modeling.
Available online xxx
Patients with a primary diagnosis of gastric cancer undergoing gastrectomy as primary procedure were included. We examined relationships between patient- and hospital-level factors,
Keywords:
surgery type, and outcomes including in-hospital mortality and length of stay (LOS).
Gastric cancer
Results: A total of 67,327 patients with gastric cancer undergoing gastrectomy nationwide
Variation
with complete information were included. Compared with patients treated in 2001, pa-
Survival
tients in 2010 were younger, more likely admitted electively, treated in a teaching hospital,
Gastrectomy
or at an urban center. There was no difference in the type of procedure performed over time. Factors associated with an increased risk of in-hospital mortality included older age, male gender, and nonelective admission (P < 0.05). In multivariable analysis, patients undergoing gastrectomy in 2010 demonstrated 40% lower odds of in-hospital mortality (odds ratio, 0.60; P ¼ 0.008). Overall mean LOS was 13.9 d (standard error, 0.1) without change over time. Factors associated with longer LOS included procedure type, hospital location, nonelective admission, and comorbid disease (all P < 0.05). Conclusions: The adjusted odds of in-hospital mortality among surgically treated patients with gastric cancer decreased >40% between 2001 and 2010. Further research is warranted to determine if these findings are due to better patient selection, regionalization of care, or improvement of in-hospital quality of care. ª 2014 Elsevier Inc. All rights reserved.
1.
Background
Gastric cancer is a leading cause of cancer death worldwide [1]. Over the past four decades, gastric cancer decreased from
being the most common cancer worldwide in 1975 to being the fifth most common neoplasm in 2012 [1]. Mortality because of gastric cancer has also decreased, but it remains the third leading cause of cancer death worldwide, contributing to
* Corresponding author. Department of Surgery, Center for Surgical Trials and Outcomes Research, Johns Hopkins School of Medicine, 600 N. Wolfe Street, Blalock 688, Baltimore, MD 21287. Tel.: þ1 410 502 2601; fax: þ1 410 955 8101. E-mail address: [email protected] (E.B. Schneider). 0022-4804/$ e see front matter ª 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jss.2014.03.015
2
j o u r n a l o f s u r g i c a l r e s e a r c h x x x ( 2 0 1 4 ) 1 e7
723,000 deaths annually [2]. Endoscopic procedures have emerged as a therapeutic alternative to surgical intervention for early-stage disease, especially in Asian countries where there is a high prevalence of gastric cancer and where patients undergo routine screening. On the contrary, in Western countries, surgery remains the main curative treatment used because most cases of gastric cancer in the West are diagnosed at an advanced stage [3]. The epidemiology of surgically treated patients with gastric cancer has been described by Smith et al. [4], who showed a relatively stable in-hospital mortality of 6% from 1998e2003, with older age, male sex, and total gastrectomy independently associated with higher in-hospital mortality. In the past 10 y, evidence-based medicine has changed many aspects in the management of gastric cancer, especially in terms of surgical methods. Previous studies found that a more conservative approach, involving less extensive resection and reduced lymph node dissection, achieved similar mortality and morbidity compared with more aggressive techniques [3]. Over the same period, there has also been a reported change in the histology and location of gastric cancer [5]. For this study, we were interested in examining possible changes in the patterns of intervention for gastric cancer and hospital-based outcomes among patients surgically treated for gastric cancer in the past decade in the United States. To our best knowledge, this issue has not been well addressed in the current literature. To understand how changes in patientand hospital-level factors, as well as surgical treatment, are associated with outcomes over the last decade, we examined a nationally representative sample of patients surgically treated for gastric cancer.
2.
Methods
2.1.
Data source
Using the Nationwide Inpatient Sample (NIS) database, a part of the Healthcare Cost and Utilization Projects, we performed a retrospective cross-sectional analysis of surgically treated patients with gastric cancer from 2001e2010. The NIS is the largest publicly available all-payer inpatient care database of the United States, which is the discharge data composed of an approximate 20% sample of the US community hospitals [6]. By design, data from the NIS can be weighted to approximate the US national population [6].
2.2.
Study population
Participants with International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes for gastrectomy (43.5e43.9, 43.91, or 43.99) as their primary procedure and diagnosis codes for gastric cancer (151.0e151.6, 151.8, or 151.9) as their primary diagnosis were considered to be surgically treated patients with gastric cancer and were included in the study (Table 1). Patients with missing information on demographic factors or key covariates were excluded.
2.3.
Covariates
Age, race, gender, hospital bed size and annual surgical volume, procedure type (total versus partial gastrectomy), emergent admission, and comorbidities were examined across the study period and were included as covariates in multivariate analysis as they were considered potential confounders based on literature review [7e14]. Differences in these factors were also examined between patients undergoing surgery in 2001 and those undergoing surgery in 2010 using Student t-test and chi-square test. Procedure type was identified using ICD-9-CM procedure codes. Patients were considered to have had a total gastrectomy if their primary procedure code was 43.9, 43.91, or 43.99; otherwise, patients were considered to have undergone a partial gastrectomy. Hospital bed size was categorized into small, medium, or large based on the hospital region [15]. To define the burden of comorbid illness among patients undergoing gastrectomy, a Charlson comorbidity index score was calculated for each individual using a previously published algorithm, which derives comorbidities (a total of 17 conditions) from the ICD-9-CM codes associated with each discharge record [16].
2.4.
Outcome
The primary outcome of interest was in-hospital mortality, specifically death before discharge from acute inpatient care. The secondary outcome of interest was length of stay (LOS), which was calculated by subtracting the admission date from the discharge date [15].
2.5.
Statistical analysis
Descriptive analysis was done to compare patients from 2001e2010. Differences in selected characteristics were determined using Student t-test for continuous variables and chi-square test for categorical variables. A P value of
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.JournalofSurgicalResearch.com
Inpatient survival after gastrectomy for gastric cancer in the 21st century Han Wang, MD, MPH, Timothy M. Pawlik, MD, MPH, PhD, Mark D. Duncan, MD, Xuan Hui, MD, ScM, Shalini Selvarajah, MD, MPH, Joseph K. Canner, MHS, Adil H. Haider, MD, MPH, Nita Ahuja, MD, and Eric B. Schneider, PhD* Department of Surgery, Center for Surgical Trials and Outcomes Research, Johns Hopkins School of Medicine, Baltimore, Maryland
article info
abstract
Article history:
Background: Surgical treatment for gastric cancer has evolved substantially. To understand
Received 4 January 2014
how changes in patient- and hospital-level factors are associated with outcomes over the
Received in revised form
last decade, we examined a nationally representative sample.
26 February 2014
Methods: Retrospective cross-sectional discharge data from the 2001e2010 Nationwide Inpa-
Accepted 5 March 2014
tient Sample were analyzed using cross tabulation and multivariable regression modeling.
Available online xxx
Patients with a primary diagnosis of gastric cancer undergoing gastrectomy as primary procedure were included. We examined relationships between patient- and hospital-level factors,
Keywords:
surgery type, and outcomes including in-hospital mortality and length of stay (LOS).
Gastric cancer
Results: A total of 67,327 patients with gastric cancer undergoing gastrectomy nationwide
Variation
with complete information were included. Compared with patients treated in 2001, pa-
Survival
tients in 2010 were younger, more likely admitted electively, treated in a teaching hospital,
Gastrectomy
or at an urban center. There was no difference in the type of procedure performed over time. Factors associated with an increased risk of in-hospital mortality included older age, male gender, and nonelective admission (P < 0.05). In multivariable analysis, patients undergoing gastrectomy in 2010 demonstrated 40% lower odds of in-hospital mortality (odds ratio, 0.60; P ¼ 0.008). Overall mean LOS was 13.9 d (standard error, 0.1) without change over time. Factors associated with longer LOS included procedure type, hospital location, nonelective admission, and comorbid disease (all P < 0.05). Conclusions: The adjusted odds of in-hospital mortality among surgically treated patients with gastric cancer decreased >40% between 2001 and 2010. Further research is warranted to determine if these findings are due to better patient selection, regionalization of care, or improvement of in-hospital quality of care. ª 2014 Elsevier Inc. All rights reserved.
1.
Background
Gastric cancer is a leading cause of cancer death worldwide [1]. Over the past four decades, gastric cancer decreased from
being the most common cancer worldwide in 1975 to being the fifth most common neoplasm in 2012 [1]. Mortality because of gastric cancer has also decreased, but it remains the third leading cause of cancer death worldwide, contributing to
* Corresponding author. Department of Surgery, Center for Surgical Trials and Outcomes Research, Johns Hopkins School of Medicine, 600 N. Wolfe Street, Blalock 688, Baltimore, MD 21287. Tel.: þ1 410 502 2601; fax: þ1 410 955 8101. E-mail address: [email protected] (E.B. Schneider). 0022-4804/$ e see front matter ª 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jss.2014.03.015
2
j o u r n a l o f s u r g i c a l r e s e a r c h x x x ( 2 0 1 4 ) 1 e7
723,000 deaths annually [2]. Endoscopic procedures have emerged as a therapeutic alternative to surgical intervention for early-stage disease, especially in Asian countries where there is a high prevalence of gastric cancer and where patients undergo routine screening. On the contrary, in Western countries, surgery remains the main curative treatment used because most cases of gastric cancer in the West are diagnosed at an advanced stage [3]. The epidemiology of surgically treated patients with gastric cancer has been described by Smith et al. [4], who showed a relatively stable in-hospital mortality of 6% from 1998e2003, with older age, male sex, and total gastrectomy independently associated with higher in-hospital mortality. In the past 10 y, evidence-based medicine has changed many aspects in the management of gastric cancer, especially in terms of surgical methods. Previous studies found that a more conservative approach, involving less extensive resection and reduced lymph node dissection, achieved similar mortality and morbidity compared with more aggressive techniques [3]. Over the same period, there has also been a reported change in the histology and location of gastric cancer [5]. For this study, we were interested in examining possible changes in the patterns of intervention for gastric cancer and hospital-based outcomes among patients surgically treated for gastric cancer in the past decade in the United States. To our best knowledge, this issue has not been well addressed in the current literature. To understand how changes in patientand hospital-level factors, as well as surgical treatment, are associated with outcomes over the last decade, we examined a nationally representative sample of patients surgically treated for gastric cancer.
2.
Methods
2.1.
Data source
Using the Nationwide Inpatient Sample (NIS) database, a part of the Healthcare Cost and Utilization Projects, we performed a retrospective cross-sectional analysis of surgically treated patients with gastric cancer from 2001e2010. The NIS is the largest publicly available all-payer inpatient care database of the United States, which is the discharge data composed of an approximate 20% sample of the US community hospitals [6]. By design, data from the NIS can be weighted to approximate the US national population [6].
2.2.
Study population
Participants with International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes for gastrectomy (43.5e43.9, 43.91, or 43.99) as their primary procedure and diagnosis codes for gastric cancer (151.0e151.6, 151.8, or 151.9) as their primary diagnosis were considered to be surgically treated patients with gastric cancer and were included in the study (Table 1). Patients with missing information on demographic factors or key covariates were excluded.
2.3.
Covariates
Age, race, gender, hospital bed size and annual surgical volume, procedure type (total versus partial gastrectomy), emergent admission, and comorbidities were examined across the study period and were included as covariates in multivariate analysis as they were considered potential confounders based on literature review [7e14]. Differences in these factors were also examined between patients undergoing surgery in 2001 and those undergoing surgery in 2010 using Student t-test and chi-square test. Procedure type was identified using ICD-9-CM procedure codes. Patients were considered to have had a total gastrectomy if their primary procedure code was 43.9, 43.91, or 43.99; otherwise, patients were considered to have undergone a partial gastrectomy. Hospital bed size was categorized into small, medium, or large based on the hospital region [15]. To define the burden of comorbid illness among patients undergoing gastrectomy, a Charlson comorbidity index score was calculated for each individual using a previously published algorithm, which derives comorbidities (a total of 17 conditions) from the ICD-9-CM codes associated with each discharge record [16].
2.4.
Outcome
The primary outcome of interest was in-hospital mortality, specifically death before discharge from acute inpatient care. The secondary outcome of interest was length of stay (LOS), which was calculated by subtracting the admission date from the discharge date [15].
2.5.
Statistical analysis
Descriptive analysis was done to compare patients from 2001e2010. Differences in selected characteristics were determined using Student t-test for continuous variables and chi-square test for categorical variables. A P value of
