Observed overall morbidity and mortality rates by age group and type of surgery. *P < .05 vs patients 55 years or younger by χ2 test with Bonferroni adjustment. GI indicates gastrointestinal; HPB, hepatobiliary or pancreatic.
Bentrem DJ, Cohen ME, Hynes DM, Ko CY, Bilimoria KY. Identification of Specific Quality Improvement Opportunities for the Elderly Undergoing Gastrointestinal Surgery. Arch Surg. 2009;144(11):1013-1020. doi:10.1001/archsurg.2009.114
Specific complications occur more frequently in elderly patients undergoing major gastrointestinal (GI) tract operations that may represent opportunities for quality improvement.
Retrospective cohort study.
One hundred twenty-one hospitals participating in American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP).
Using the ACS-NSQIP participant use file (2005-2006), patients undergoing upper gastrointestinal tract (n = 4115), hepatobiliary or pancreatic (n = 3364), and colorectal (n = 17 268) operations at 121 hospitals were examined.
Main Outcome Measures
Risk-adjusted 30-day outcomes were assessed using regression modeling adjusting for patient characteristics, comorbidities, and surgical procedures. The elderly were defined as those older than 75 years.
Between January 1, 2005, and December 31, 2006, a total of 54 747 patients who underwent major GI tract operations were identified from the ACS-NSQIP data file. In the elderly, overall perioperative morbidity was 1.2 to 2 times higher and mortality was 2.9 to 6.7 times higher than in younger patients after adjusting for differences in preoperative comorbidities. Irrespective of procedure type, the elderly were significantly more likely to experience cardiac (acute myocardial infarction and cardiac arrest), pulmonary (pneumonia, pulmonary embolism, and respiratory failure), and urologic (urinary tract infection and renal failure) complications. However, surgical site infections, postoperative bleeding events, deep venous thromboses, and rates of return to the operating room did not differ significantly by age.
Morbidity and mortality are markedly higher in older patients. Quality measures for the elderly currently address only myocardial infarction, surgical site infection, and deep venous thrombosis. If care for the elderly is to be improved, quality improvement initiatives need to be expanded to include postoperative pulmonary and renal complications.
The geriatric population represents one of the fastest growing subsets of the US population. By 2030, it is estimated that 20% of the total population will be older than 75 years.1 As the population ages, an increasing number of elderly patients will require major gastrointestinal (GI) tract surgery.2 By 2020, the number of elderly patients undergoing major oncologic procedures is expected to increase more than 50%.3
Recent population-based findings have highlighted elevated risks of overall morbidity and mortality for elderly patients undergoing GI tract operations.4 Moreover, there is significant variability among hospitals in outcomes for the elderly.5 Therefore, it is important to understand what certain hospitals do to have better outcomes for elderly patients. Quality assessment and feedback have been suggested as mechanisms to improve care at underperforming hospitals.6
Few current quality improvement initiatives focus on the elderly. The Centers for Medicare and Medicaid Services Physician Quality Reporting Initiative is a rapidly growing program of quality assessment that examines performance measures related to cardiac complications, deep venous thrombosis and pulmonary embolism, and surgical site infection. With ongoing initiatives to assess quality in health care, specific evidenced-based quality improvement targets are needed to measure performance and to help hospitals direct quality improvement efforts, particularly for the growing population of elderly patients.
Oversight agencies and payers seek to identify select complications for quality measurement programs. However, national and hospital resources for quality improvement are limited, and focusing these programs on specific areas will be beneficial. The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) offers a large data set of clinical data collected in standardized fashion to assess outcomes in the elderly.7,8 Because age is a risk factor for increased morbidity after major surgery4,9,10 and because information regarding the frequency of specific complications in the elderly is lacking, we sought to identify specific complications that occur more frequently in elderly patients undergoing upper GI tract, hepatobiliary or pancreatic (HPB), and colorectal operations to provide additional evidence-based targets for quality improvement initiatives.
We used the 2005-2006 ACS-NSQIP Participant Use Data File,16 which is deidentified and Health Insurance Portability and Accountability Act compliant, to perform a retrospective cohort study of patients undergoing upper GI tract, HPB, and colorectal operations. Originally developed as a quality improvement initiative by the Veterans Health Administration in 1994,11 the ACS-NSQIP (http://www.acsnsqip.org/) is a prospective multi-institutional risk-adjusted outcomes program that provides participating hospitals with data for the purposes of quality improvement.12 The ACS-NSQIP data set contains information on 152 490 patients who underwent surgery in 2005 and 2006 at 121 hospitals (59% academic and 41% community).13
The details of the ACS-NSQIP sampling methods, data abstraction process, variables included, and outcomes monitored have been previously described.7,8,14 Briefly, the program collects detailed data regarding patient demographics, preoperative risk factors, and laboratory values before the index surgical procedure. Intraoperative variables are also collected. Postoperative outcomes (including mortality, reoperation, length of stay, respiratory events, renal complication, cardiac complications, surgical site infections, central nervous system events, and other events) are evaluated at 30 days after surgery irrespective of whether the event occurs as an inpatient or outpatient or on readmission to another hospital. The sampling strategy currently requires hospitals to report their first 40 consecutive eligible cases on an 8-day cycle such that each subsequent cycle starts on a different day of the week to capture a variety of cases and surgeons and to minimize bias in case selection.15 Major cases are eligible for inclusion, and certain cases with low morbidity and mortality are limited to fewer than 3 cases per cycle (eg, lumpectomy and inguinal herniorrhaphy). To ensure consistency and accuracy, data abstraction is overseen at each hospital by surgical clinical nurse reviewers who are required to be certified through an initial intensive training process, with subsequent continuing education courses to standardize data abstraction.16 The surgical quality improvement nurse submits data to the ACS-NSQIP through a secure Web-based system with built-in software checks and user information prompts to ensure completeness, uniformity, and validity of the data. Data automation tools are available to lower the data entry burden on the surgical quality improvement nurses and to improve the quality of data being captured. Data consistency and reliability are assessed annually for every hospital through an on-site audit during which an interrater reliability analysis is performed.17,18
All patients who underwent a major GI tract resection that constitutes more than 1% of cases in the ACS-NSQIP data set were identified using Current Procedural Terminology codes.19,20 These procedures were divided into the following 3 heterogeneous groups: upper GI tract (gastrectomy, esophagectomy, paraesophageal hernia repairs, and fundoplication [bariatric procedures were excluded]), HPB (hepatectomy, pancreatectomy, splenectomy, and choledochoenterostomy), and colorectal (colectomy, proctectomy, small-bowel resection, rectal prolapse repair, and colostomy reversal). The following high-risk patients were excluded: patients who had disseminated cancer, underwent emergent operations, had preoperative mechanical ventilator dependence, had preoperative renal failure (acute or requiring dialysis), had an American Society of Anesthesiologists class 5 status, or had preoperative sepsis or systemic inflammatory response syndrome.
Potential independent variables included patient demographics, preexisting comorbidities, preoperative laboratory values, and intraoperative variables. Standard definitions for these variables have been described previously.21 Patient age was categorized as 55 years or younger, 56 to 65 years, 66 to 75 years, or older than 75 years. Patient demographic variables included sex and race/ethnicity (white, black, or other). Lifestyle factors consisted of smoking (≤1 year before surgery) and alcohol intake (>2 drinks per day). The patient's preoperative status was evaluated according to American Society of Anesthesiologists class (1 or 2 vs 3 or 4) and functional status (independent vs partially or totally dependent). Comorbidity variables evaluated include the following: bleeding disorders, presence or absence of ascites, chronic obstructive pulmonary disease, renal failure (acute or chronic disease), congestive heart failure (≤30 days before surgery), diabetes mellitus (requiring oral medication or insulin vs none), peripheral vascular disease (rest pain, gangrene, amputation, claudication, or revascularization for peripheral vascular disease), coronary artery disease (angina, cardiac surgery, percutaneous cardiac intervention, or myocardial infarction ≤6 months of surgery), or neurologic event or disease (paraplegia, hemiplegia, quadriplegia, impaired sensorium, transient ischemic attacks, or stroke with or without residual deficit). Other variables assessed were corticosteroid use for a chronic condition, transfusion requirements (intraoperative or postoperative vs none), and weight loss exceeding 10% of body weight in the 6 months before surgery. Laboratory values were dichotomized using NSQIP definitions of abnormal values. Missing laboratory values were examined using indicator variables. Within the upper GI tract, HPB, and colorectal categories, similar Current Procedural Terminology codes were grouped into a categorical variable.
Standard definitions for NSQIP outcomes have been described previously.21 Patients were followed up for 30 days in-hospital and as outpatients. Information regarding whether a postoperative complication occurred was obtained from patient hospital charts and office charts and by contacting the patient directly if needed. Thirty-day outcomes examined included the following: surgical site infection, pneumonia, pulmonary embolism, unplanned intubation, renal failure, urinary tract infection, mechanical ventilator dependence for longer than 48 hours, stroke, coma for longer than 24 hours, cardiac arrest, myocardial infarction, bleeding requiring transfusion, deep venous thrombosis, or sepsis. The occurrence of any of these postoperative complications (overall morbidity) was also assessed. In addition, return to the operating room within 30 days was assessed. Thirty-day mortality was evaluated irrespective of whether the death occurred in the hospital, after patient discharge, or following readmission to another hospital. Length of stay after the index surgery was dichotomized based on the median length of stay.
Continuous variables were compared using t test for equality of means. Categorical variables were compared using χ2 test for differences in proportions. Medians were compared using Mann-Whitney test. The association between potential predictor variables and the occurrence of any adverse event was assessed using χ2 test. Variables with P < .20 on bivariate analysis were examined in a forward stepwise multiple logistic regression model to assess the association between patient age and specific postoperative outcomes. The age variable was forced into the regression model. Odds ratios with 95% confidence intervals were generated. The Hosmer-Lemeshow goodness-of-fit test and the C index were used to assess the models.22 The means of the expected values generated from the logistic models were used to estimate the risk-adjusted event rate by age. All analyses were performed using commercially available software (SPSS, version 15; SPSS Inc, Chicago, Illinois). P < .05 was considered statistically significant. All P values reported are 2-sided. This study was approved by the institutional review board of Northwestern University, Chicago.
Between January 1, 2005, and December 31, 2006, a total of 24 747 patients were identified from the ACS-NSQIP data file who underwent major GI tract surgical procedures (Table 1). The abnormal preoperative laboratory values are summarized in Table 2. At 121 hospitals, 4115 patients underwent upper GI tract operations, 3364 patients underwent HPB operations, and 17 268 patients underwent colorectal surgery.
Elderly patients (>75 years) had significantly higher overall morbidity (25.8% for upper GI tract, 33.7% for HPB, and 27.3% for colorectal) and 30-day perioperative mortality (5.7% for upper GI tract, 4.7% for HPB, and 4.2% for colorectal) than younger patients undergoing major GI tract operations (Figure). Overall perioperative morbidity was 1.2 to 2 times higher and mortality was 2.9 to 6.7 times higher for elderly patients compared with younger patients after adjusting for differences in preoperative comorbidities (Table 3). In addition, patients older than 75 years were significantly more likely to have an extended postoperative length of stay. Approximately 60% of patients older than 75 years remained in the hospital longer than 7 days after a major GI tract operation (61.0% for upper GI tract, 62.2% for HPB, and 58.1% for colorectal).
Irrespective of procedure type, the elderly were significantly more likely than younger patients to experience cardiac (acute myocardial infarction and cardiac arrest), pulmonary (pneumonia, pulmonary embolism, and respiratory failure), and urologic (urinary tract infection and renal failure) complications. Cardiac complications were 14 to 18 times higher for elderly patients compared with younger patients after adjusting for differences in preoperative comorbidities. After upper GI tract surgery, 1.7% of patients older than 75 years experienced cardiac arrest (1.2% after HPB surgery and 0.9% after colorectal surgery) (Table 3). Pulmonary complication rates were 1.5 to 5.1 times higher for elderly patients compared with younger patients after adjusting for differences in preoperative comorbidities. Between 2.4% (upper GI tract surgery group) and 6.3% (colorectal surgery group) of elderly patients developed pneumonia (5.7% of the HPB surgery group developed pneumonia). Between 4.5% (colorectal surgery group) and 7.9% (upper GI tract surgery group) of elderly patients had an unplanned intubation (4.8% of the HPB group had an unplanned intubation). Urologic complication rates were 1.3 to 6.8 times higher for elderly patients compared with younger patients after adjusting for differences in preoperative comorbidities. Between 0.9% (upper GI tract surgery group) and 3.6% (HPB surgery group) of elderly patients experienced renal failure after operation (2.1% of the colorectal surgery group experienced renal failure). However, there was no elevated risk of wound complications, deep venous thrombosis, return to the operating room, or postoperative bleeding requiring transfusion for patients older than 75 years compared with younger patients (Table 4).
Although the elderly population continues to grow, current information about specific complications for the elderly undergoing major GI tract operations is mainly limited to case series from select centers.23,24 A consensus statement by the American Medical Association concluded that “one of the most important tasks that the medical community faces today is to prepare for the problems in caring for the elderly.”25(p2460) Standardized, clinically collected, multi-institutional data such as those from the ACS-NSQIP can provide estimates of the risks for specific complications. We focused on major abdominal operations, including upper GI tract, HPB, and colorectal surgical procedures, to identify specific complications for which older patients undergoing elective GI tract operations have significantly higher postoperative risk.
Prior studies7,26 have identified the elderly as an “at-risk” population when undergoing major abdominal operations. Finlayson et al4 examined the risk of perioperative mortality using the National Inpatient Sample for patients undergoing esophageal and pancreatic resection and found that perioperative mortality was up to 3 times higher for elderly patients compared with younger patients in the general population. They concluded that there is a need for improvement in the surgical management of the elderly and that identification of perioperative processes of care or risk factors would help focus efforts to improve outcomes and optimize care in this vulnerable population. Turrentine et al10 examined institutional NSQIP data from the University of Virginia and found increased surgical morbidity and mortality in the elderly for a wide range of procedures. For patients older than 70 years, morbidity was more than 42% and mortality was more than 4.3%. Preoperative transfusion, emergency operation, and weight loss were the most powerful predictors associated with morbidity in elderly patients.
Other studies have evaluated risks of overall morbidity and mortality for the elderly undergoing specific complex operations. Studies have shown elevated risk of perioperative mortality associated with esophagectomy27,28 and gastrectomy.24,29 For elderly patients undergoing pancreatic or hepatic resections, Fong et al30 found no elevated risk of perioperative morbidity or mortality. Morbidity rates have varied from 21% to 28% among elderly patients.10 Single-institution series have examined highly selected patient populations and have represented specialized centers. We found that overall perioperative morbidity was 1.2 to 2 times higher and perioperative mortality was 2.9 to 6.7 times higher for elderly patients compared with younger patients undergoing major GI tract surgery, even after adjusting for differences in preoperative risk factors and type of surgery.
Aging can cause a gradual progressive loss in the biologic reserve to maintain physiologic homeostasis under stress. In addition, many older adults have 1 or more chronic conditions, which further decrease the ability to respond to stress. Institutional series examining outcomes for elderly patients have found higher morbidity associated with most cardiac or pulmonary complications.31- 33 Fielding et al32 found that 55% of in-hospital mortality for elderly patients after colon cancer resection was related to conditions “indirectly related to the operation” (ie, were cardiopulmonary complications). Turrentine et al10 found that age was significantly associated with wound, renal, cardiovascular, and respiratory complications after general, thoracic, and vascular surgery. Poon et al28 found no elevated risk of major postoperative morbidity such as wound dehiscence or anastomotic leakage but found an elevated risk of cardiopulmonary morbidity. In our study, risks of cardiac, pulmonary, and renal (renal failure and urinary tract infection) complications were significantly elevated for elderly patients undergoing upper GI tract, HPB, or colorectal surgery. There was no elevated risk of wound disruption for elderly patients. We found no elevated risk of wound infection after upper GI tract or HPB surgery.
Finlayson et al4 found that length of stay for elderly patients after pancreas cancer surgery averaged 3 days longer for patients older than 80 years compared with younger patients; however, there was no difference in length of stay between age groups after esophageal resection. Among patients undergoing colon surgery for cancer, Hobler34 identified a significantly longer length of stay for patients older than 80 years compared with younger patients (18 vs 15 days). We found no difference in the reoperation rate for older patients after major GI tract surgery but found that the risk of extended length of stay beyond 7 days was 1.7 to 2.4 times higher for elderly patients compared with younger patients undergoing upper GI tract, HPB, and colorectal surgery.
The results of this study should be interpreted with consideration of certain limitations. First, our study has the limitations associated with large multi-institutional databases such as errors in coding and sampling; however, all ACS-NSQIP hospitals use well-defined standardized data definitions, and an annual on-site evaluation ensures adherence with these data standards.35,36 Second, the ACS-NSQIP does not collect data on complications specific to certain operations (such as anastomotic breakdown) but rather on complications that mostly are relevant to all procedures. Although we did not study these, procedure-specific outcomes may offer high-yield opportunities to improve care for the elderly. Third, the study results may not be generalizable to all hospitals, as the sites participating in the ACS-NSQIP are usually larger and higher-volume institutions, although the ACS-NSQIP includes a growing number of lower-volume community hospitals. Despite these limitations, the ACS-NSQIP offers a powerful opportunity to assess the risk of specific complications in a large cohort from multiple institutions.
When assessing postoperative risk, the patient characteristics and comorbidities must be considered.37 Careful preoperative evaluation of cardiopulmonary function remains important to risk stratify and possibly to prevent postoperative morbidity and mortality in the elderly. After adjusting for preoperative comorbidities using data from 121 hospitals, we found that elderly patients undergoing major GI tract surgery had up to a 2-fold higher risk of experiencing a complication and up to a 6.7-fold higher risk of perioperative mortality. In-hospital costs in the first year of treatment of malignant neoplasm in the GI tract have been shown to represent 60% to 80% of $21 billion spent on elderly patients diagnosed as having cancer in 2004.38 Therefore, in-hospital processes should be monitored and focused on lowering the risks of cardiac, pulmonary, and renal (renal failure and urinary tract infection) complications to improve the effectiveness and efficiency of care for the elderly patients undergoing major operation. McGory et al39 developed process-based quality indicators specific to the elderly undergoing a major abdominal operation. Seventy-six process indicators were validated by an expert panel. Many of these indicators address the high-risk areas identified in the present study and are the focus of the measures identified by McGory et al; these include cardiopulmonary complications (extensive preoperative evaluations and perioperative β-blocker therapy) and urologic complications (fever workup, timely removal of urinary catheters, laboratory evaluation of renal function, and protocols for prevention of dehydration). Institutions should not only identify an “in-hospital team” of providers to prevent likely complications for the elderly but also commence explicit evaluation before operation and continue needs assessment after discharge with the goal of maintaining preoperative levels of functioning.
In this multi-institutional study, elderly patients undergoing major upper GI tract, HPB, or colorectal operations had higher perioperative risks than younger patients. Current quality measures for the elderly (such as Medicare's Surgical Care Improvement Program) address only myocardial infarction, surgical site infection, and deep venous thrombosis. Our data reveal targets and opportunities for improving care for elderly patients. If care for the elderly is to be improved, quality improvement initiatives need to be expanded to include pulmonary and urologic complications.
Correspondence: Karl Y. Bilimoria, MD, MS, Division of Research and Optimal Patient Care, American College of Surgeons, 633 N St Clair St, 22nd Floor, Chicago, IL 60611 (firstname.lastname@example.org).
Accepted for Publication: October 7, 2008.
Author Contributions:Study concept and design: Ko and Bilimoria. Acquisition of data: Ko and Bilimoria. Analysis and interpretation of data: Bentrem, Cohen, Hynes, Ko, and Bilimoria. Drafting of the manuscript: Bentrem and Bilimoria. Critical revision of the manuscript for important intellectual content: Bentrem, Cohen, Hynes, Ko, and Bilimoria. Statistical analysis: Bentrem, Cohen, and Bilimoria. Obtained funding: Ko. Administrative, technical, and material support: Hynes and Ko. Study supervision: Ko.
Financial Disclosure: None reported.
Funding/Support: This study was funded in part by grant ACSIRG 93-037-12 from the American Cancer Society Illinois Division and by the Barnum Foundation (Dr Bentrem). Dr Hynes is supported by the Department of Veterans Affairs Health Services Research and Development Service Research Career Scientist Award. Dr Bilimoria is supported by the American College of Surgeons Clinical Scholars in Residence program.
Disclaimer: The ACS-NSQIP and the hospitals participating in the ACS- NSQIP are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.