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Using the National Surgical Quality Improvement Program to Study Outcomes in Colon and Rectal Surgery
Using the National Surgical Quality Improvement Program to Study Outcomes in Colon and Rectal Surgery Marcia McGory Russell, MD The American College of Surgeons’ National Surgical Quality Improvement Program (NSQIP) has been used extensively within the field of colon and rectal surgery to evaluate risk-adjusted outcomes after surgical intervention for common colorectal problems, including appendicitis, colorectal cancer, diverticulitis, inflammatory bowel disease, and rectal prolapse. In addition, NSQIP has been used to evaluate patient-specific risk factors (eg, age, body mass index, preoperative anemia), procedure-specific risk factors (eg, laparoscopic approach, emergency surgery), as well as specific outcomes after surgery (eg, length of stay, postdischarge venous thromboembolism, and return to operating room). NSQIP has both significant strengths as well as limitations. Areas for future NSQIP research and development include addition of disease-specific and operation-specific variables as well as more projects aimed at feeding back NSQIP data as a mechanism for quality improvement. Semin Colon Rectal Surg 23:164-170 Published by Elsevier Inc.
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he development of the American College of Surgeons’ (ACS) National Surgical Quality Improvement Program (NSQIP) has significantly enhanced our ability to evaluate outcomes after surgery. The goal of the current manuscript is to provide an overview of the types of research that have been performed using NSQIP within the field of colorectal surgery. Abstracts were identified through PubMed search (through October 2011) using the following key words: “NSQIP,” “National Surgery Quality Improvement Program,” “colon,” “rectal,” and “colorectal.” Abstracts were reviewed for content relevant to measuring quality and outcomes in colon and rectal surgery. A summary of published research using NSQIP to evaluate outcomes in colon and rectal surgery appears later in the text in addition to a discussion of NSQIP limitations and areas for future research.
Department of Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA. Address reprint requests to: Marcia McGory Russell, MD, Department of Surgical and Perioperative Care, VA Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Building 500, 6th Floor, 6 West, Mail Code 10H2, Los Angeles, CA 90073. E-mail: mrussell@mednet. ucla.edu
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1043-1489/$-see front matter Published by Elsevier Inc. http://dx.doi.org/10.1053/j.scrs.2012.07.006
Benign Disease Several studies examine outcomes after colorectal surgery for benign disease, including appendicitis, diverticulitis, inflammatory bowel disease, and rectal prolapse.
Appendicitis Ingraham et al1 compared outcomes after laparoscopic versus open appendectomy for acute appendicitis. A cohort of 32,683 patients undergoing appendectomy was identified using ACS-NSQIP from 2005 to 2008; most of the patients underwent laparoscopic (vs open) approach (76.4% vs 23.6%). Patients undergoing laparoscopic appendectomy had significantly lower odds of experiencing both overall morbidity (odds ratio [OR]: 0.6) and surgical site infection (SSI, OR: 0.6). In contrast, the subset of patients with complicated appendicitis who underwent laparoscopic appendectomy had higher odds (OR: 1.4) of developing organ space SSI. The authors concluded that laparoscopic appendectomy is associated with lower overall morbidity in selected patients. Fleming et al2 attempted to address the issue of increased organ space infection in patients undergoing laparoscopic appendectomy. Using NSQIP, 35,950 patients undergoing appendectomy were identified; 77% underwent laparoscopic appendectomy. Multivariate analysis revealed that laparoscopic appendectomy decreased the odds of incisional infection
NSQIP to study outcomes in colon and rectal surgery (OR: 0.4) but increased the odds of organ space infection (OR: 1.4). A unique feature of this study was using the multivariate model to calculate the probability of organ space infection based on specific clinical scenarios. For example, a 77-year-old male patient with clinical scenario of diabetes, smoker, sepsis, preoperative white blood cell count of 17, American Society of Anesthesiologists (ASA) class 4, emergency operation, wound class IV, and operative time of ⬎60 minutes had a predicted probability of organ space infection of 12.3% for laparoscopic approach and 8.9% for open approach. The authors concluded that laparoscopic appendectomy is associated with increased risk of organ space infection but decreased risk of incisional infection. Importantly, the degree of the increased risk for organ space infection is increased by patient-specific and procedure-specific risk factors, which may influence the choice of laparoscopic versus open approach for appendectomy. Multiple other articles use NSQIP to evaluate the benefits of laparoscopic appendectomy with respect to elderly patients, complicated appendicitis, and outcomes, including operative time, length of stay (LOS), and perioperative morbidity and mortality.3-5
Diverticulitis Gawlick et al6 used NSQIP to identify patients with perforated diverticulitis undergoing emergent operative intervention. Outcomes were compared by surgical intervention: primary colectomy with anastomosis and diverting loop ileostomy versus partial colectomy with end colostomy (ie, Hartmann procedure). A total of 2018 patients with perforated diverticulitis requiring surgery were identified from 2005 to 2008; the majority (83%) underwent Hartmann procedure. Using multivariate analysis, there was no significant difference between the 2 surgical procedures with respect to the odds of wound infection, organ space infection, wound dehiscence, return to the operating room, need for postoperative mechanical ventilation, sepsis, or death. A subgroup analysis of patients with dirty/infected wounds (vs contaminated wounds) revealed significantly higher odds of death with primary anastomosis and diverting loop ileostomy compared with Hartmann procedure (OR: 2.0). The authors concluded that primary resection and anastomosis with diverting loop ileostomy should be considered in selected patients owing to the decreased morbidity associated with loop ileostomy reversal in comparison with Hartmann reversal.
Inflammatory Bowel Disease Lee et al7 evaluated the outcomes of ileocolic resection for Crohn’s disease using NSQIP from 2005 to 2009. A total of 1917 patients undergoing ileocolic resection for Crohn’s disease were identified; 34% of the resections were performed laparoscopically. Patients undergoing laparoscopic ileocolic resection had significantly lower rates of both major (7.6% vs 14.5%) and minor (9.2% vs 12.7%) complications compared with those undergoing open ileocolic resection. These findings were confirmed on multivariate analysis, with laparoscopic approach demonstrating significantly lower odds of
165 both major (OR: 0.6) and minor (OR: 0.6) complications. The authors concluded that laparoscopic ileocolic resection for Crohn’s disease is safer than the open approach. Of note, none of the articles identified addressed outcomes for ulcerative colitis patients undergoing surgery.
Rectal Prolapse The author and her colleagues from the Lahey Clinic compared outcomes after transabdominal versus transperineal repair for rectal prolapse.8 They identified a cohort of 1485 patients undergoing rectal prolapse surgery using ACSNSQIP from 2005 to 2008. The abdominal approach for rectal prolapse had significantly higher rates of infectious (9.8% vs 3.7%) and overall (12.9% vs 7.6%) complications in comparison with the transperineal approach. Multivariate analysis demonstrated that ASA class 4 (OR: 6.4) and abdominal approach (OR: 2.3) were risk factors for overall complications, whereas ASA class 4 (OR: 7.5), body mass index (BMI) ⱖ25 (OR: 1.8), and abdominal approach (OR: 2.8) were risk factors for infectious complications. We concluded that patients with significant comorbidities (as measured by ASA class or high BMI) may be at higher risk for postoperative complications and should be considered for transperineal rather than abdominal approach.
Patient-Specific Risk Factors Body Mass Index Merkow et al9 evaluated the effect of BMI on short-term outcomes after colectomy for colon cancer using the ACS-NSQIP database. The authors identified 3202 patients who underwent colectomy for cancer in 2007. Using multivariate logistic regression, they evaluated the independent impact of BMI on specific complications (ie, SSI) as well as overall morbidity. Morbidly obese patients had significantly higher odds than normal-weight patients of superficial SSI (OR: 3.1), deep SSI (OR: 4.2), wound dehiscence (OR: 3.5), pulmonary embolus (OR: 7.0), and renal failure (OR: 2.8). In contrast, obese patients only experienced a higher risk of pulmonary embolus (OR: 5.1) in comparison with normal-weight patients. Finally, overweight patients experienced higher odds of both SSI (OR: 1.8) and pulmonary embolism (OR: 5.1) in comparison with normal-weight patients. With respect to overall morbidity, morbidly obese patients had a 1.7-fold higher odds of any perioperative complication after colectomy for cancer, whereas overweight patients had a 1.3-fold higher odds, in comparison with normal-weight patients. The authors concluded that obesity does not appear to impact mortality or other types of complications after colon cancer surgery, like other infections (ie, pneumonia, urinary tract infection, sepsis), prolonged intubation, myocardial infarction, stroke, or reoperation.
Preoperative Anemia Leichtle et al10 used NSQIP from 2005 to 2008 to determine whether preoperative anemia adversely affects outcomes in colon and rectal surgery. The authors looked at the outcomes
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166 of increased LOS in addition to a composite outcome, including myocardial infarction, stroke, progressive renal insufficiency, and death within 30 days of surgery. Anemia was classified into 4 categories based on preoperative hematocrit: severe (21%-25%), moderate (26%-29%), mild (30%-37%), and no anemia (ⱖ38%). The distribution of patients undergoing colon and rectal surgery by anemia group was as follows: 52.6% no anemia, 38.7% mild, 7.4% moderate, and 1.3% severe. Using logistic regression analysis with propensity score matching, patients with anemia had significantly higher odds of both the composite outcome (1.8 higher odds for severe anemia, 2.2 for moderate, and 1.5 for mild) and LOS (3 days for severe anemia, 1.9 days for moderate, and 0.6 days for mild) compared with patients without anemia. The authors concluded that preoperative anemia is an independent risk factor for postoperative complications as well as prolonged hospital stay.
Procedure-Specific Risk Factors Laparoscopy Greenblatt et al11 evaluated short-term outcomes after laparoscopic-assisted proctectomy for rectal cancer using the ACS-NSQIP database. From 2005 to 2009, 5420 patients were identified who underwent surgery for rectal cancer; 19% of these patients underwent laparoscopic-assisted proctectomy. The open proctectomy group had a significantly higher 30-day complication rate than the laparoscopic-assisted proctectomy group (28.8% vs 20.5%, P ⬍ 0.0001). Specifically, the open proctectomy group had higher rates of superficial SSI, sepsis, respiratory complications, renal failure, and venous thromboembolism (VTE) when compared with the laparoscopic-assisted proctectomy group. In addition, the patients undergoing laparoscopic-assisted proctectomy had lower rates of intraoperative blood transfusion (4.3% vs 12.3%, P ⬍ 0.0001) and shorter LOS (median 5 vs 7 days, P ⬍ 0.0001). On multivariate analysis to identify predictors of morbidity, open proctectomy had significantly higher odds of 30-day morbidity in comparison with laparoscopic-assisted proctectomy (OR: 1.4). The authors concluded that laparoscopic-assisted proctectomy was associated with shorter LOS and decreased 30-day morbidity compared with open proctectomy. Stewart et al12 evaluated laparoscopic versus open abdominoperineal resection (APR) using 2005-2008 NSQIP data. The goal was to evaluate variables that influenced the type of surgical approach as well as identify predictors of postoperative complications. A total of 1340 patients were identified; 10.7% underwent laparoscopic APR. Factors associated with significantly increased odds of undergoing laparoscopic APR were female gender (OR: 1.6), non-Caucasian race (1.5), and BMI ⬍25 (OR: 1.5). With respect to postoperative complications, there was no significant difference in complication rates by surgical approach (open APR: 64%; laparoscopic APR: 53%). Predictors of complications after open APR were tobacco use (OR: 1.8), history of cerebrovascular accident (OR: 2.4), and ⬎10% weight loss before surgery (OR: 1.6).
The only predictor of complications after laparoscopic APR was systemic hypertension (OR: 2.5). The authors concluded that few patients are being offered laparoscopic APR due to surgeon preference rather than patient-specific factors, as the overall complication rate is similar between laparoscopic and open APR. Bilmoria et al13 used NSQIP to compare short-term outcomes of laparoscopic-assisted versus open colectomy for colon cancer. During 2005-2006, the authors identified 3059 patients who underwent colectomy for treatment of colon cancer; 27.4% underwent laparoscopic-assisted colectomy. Patients undergoing laparoscopic-assisted colectomy had lower rates of any adverse event (14.6% vs 21.7% in open colectomy), especially infectious complications like SSI (9.1% vs 11.8%), urinary tract infection (1.9% vs 3.2%), and pneumonia (1.8% vs 3.4%). The rate of wound disruption/ dehiscence was also notably lower in these patients (0.5% vs 1.5%). These results were confirmed on multivariate analysis because patients undergoing open colectomy had higher odds of any adverse event (OR: 1.5) as well as specific complications like SSI (OR: 1.3), wound disruption/dehiscence (OR: 3.0), pneumonia (OR: 1.8), and urinary tract infection (OR: 1.8). The authors concluded that laparoscopic-assisted colectomy for colon cancer was associated with lower postoperative morbidity, especially for infectious complications. McCloskey et al14 used NSQIP to evaluate laparoscopic colorectal surgery in the high-risk patient, as defined by a NSQIP-predicted complication rate of ⬎15%. The authors identified consecutive patients undergoing laparoscopic or open colectomy from 2002 to 2004 and used NSQIP to classify these patients as high or low risk based on the NSQIPpredicted complication rate for each patient. Forty-five highrisk patients were identified, and the patients undergoing laparoscopic colectomy had significantly lower major complications than those undergoing open colectomy (4% vs 41%). The LOS was also significantly shorter in the laparoscopic group (5 vs 8 days). The authors concluded that laparoscopic colorectal surgery is safe in patients predicted to have high postoperative morbidity and mortality. Kiran et al15 used NSQIP from 2006 to 2007 to evaluate the outcome of SSI between patients undergoing laparoscopic and open colorectal surgery. A total of 10,979 patients underwent colorectal surgery during this period; 31.1% of the cases were performed laparoscopically. The overall rate of SSI was 14% and was significantly higher in the open compared with the laparoscopic group (16.1% vs 9.5%). Multivariate analysis revealed that age; open surgical approach; ASA score of ⱖ3; smoking; diabetes; operative time of ⬎180 minutes; diagnoses of appendicitis, diverticulitis, or regional enteritis (Crohn’s disease); and operations involving the rectum (coloproctostomy, Hartmann procedure, and low pelvic anastomosis) were associated with significantly higher odds of SSI. The authors concluded that laparoscopy is independently associated with a lower rate of SSI in colorectal surgery.
Emergency Surgery Ingraham et al16 used NSQIP from 2005 to 2007 to compare hospital performance in nonemergency versus emergency
NSQIP to study outcomes in colon and rectal surgery colorectal operations. The authors identified a cohort of 25,710 patients undergoing nonemergency colorectal resection and 5083 undergoing emergency colorectal resection. Both morbidity (48% emergency vs 23.9% nonemergency) and mortality (15.3% emergency vs 1.9% nonemergency) rates were significantly higher in the group of patients undergoing emergency surgery. Of note, a hospital’s observed/expected ratios after nonemergency and emergency colorectal operations were weakly correlated for morbidity (Pearson correlation coefficient: 0.3) and minimally correlated for mortality (Pearson correlation coefficient: 0.2). In addition, hospital rankings changed when comparing both morbidity and mortality after nonemergency versus emergency colorectal operations. The authors concluded that hospitals with good outcomes after nonemergency colorectal operations do not necessarily have comparable outcomes after emergency colorectal operations, which may identify an area for quality improvement.
Specific Patient Population: Elderly Al-Refaie et al17 used NSQIP to compare outcomes after colorectal cancer surgery in the oldest-old (ⱖ80 years) with a younger cohort (40-55 years). The oldest-old experienced significantly higher rates of 30-day mortality (6% vs ⬍1%) and major complications (21% vs 14%) in comparison with younger patients. The oldest-old also had significantly longer LOS after both open and laparoscopic procedures in comparison with younger patients. The authors used multivariate analysis to identify predictors of 5 outcomes: (1) 30-day mortality, (2) major complications after open colorectal cancer surgery, (3) major complications after laparoscopic colorectal cancer surgery, (4) prolonged LOS after open colorectal cancer surgery, and (5) prolonged LOS after laparoscopic colorectal cancer surgery. The following variables were predictive of increased odds of all 5 outcomes: age ⱖ80 years, ASA score of 3 or 4, and ⱖ2 U of red blood cell transfusion. The authors concluded that the effects of older age not only influence mortality but also other outcomes like morbidity and LOS. Kennedy et al18 sought to optimize surgical care for older patients with colon cancer. They used NSQIP from 2005 to 2008 to identify 5914 patients aged 65 years or older who underwent surgery for colon cancer. The outcome of interest was 30-day morbidity or 30-day mortality, and the authors had a special interest in evaluating the impact of laparoscopic versus open surgery for elderly patients with colon cancer. To statistically compensate for nonrandom assignment to laparoscopic versus open surgery, they used propensity score matching. Elderly patients undergoing laparoscopic surgery had significantly lower rates of postoperative morbidity (16.1% vs 25.4%) and mortality (2.1% vs 3.7%) compared with those undergoing open surgery. Factors predictive of both 30-day morbidity and 30-day mortality included open surgery, age ⬎75 years, totally/partially dependent functional status, presence of ascites, and ASA class 2 or 3. The
167 authors concluded that expanding laparoscopic procedures in the elderly population may improve outcomes for patients with colon cancer. Kwok et al19 sought to develop a preoperative risk prediction tool for patients aged 80 years or older needing an emergency colectomy. The prediction tool was created using ACSNSQIP data from 2007 to 2008. The 8 variables most significantly associated with mortality in the elderly population needing emergency colectomy were as follows: age 80-89 years, totally dependent functional status, history of chronic obstructive pulmonary disease, history of congestive heart failure, metastatic cancer, preoperative steroids, systemic inflammatory response syndrome, and creatinine ⬎1.5 mg/dL. This targeted risk tool correctly predicted mortality 56% of the time (when there was 80% specificity), which was better than prediction of mortality using the ASA score, the Surgical Risk Scale (uses ASA score along with urgency and complexity of operation), and the ACS Colorectal Surgery Risk Calculator, described later in the text. The authors concluded that because their targeted risk prediction tool has better discriminating power than other more generic risk prediction tools, more specialized risk assessment tools may need to be developed for specific procedures as well as specific patient populations, like the elderly population. Bentrem et al20 used NSQIP to identify specific quality improvement opportunities for elderly patients undergoing gastrointestinal surgery. They used NSQIP from 2005 to 2006 to identify patients undergoing upper gastrointestinal tract, hepatobiliary or pancreatic, and colorectal surgery and evaluated risk-adjusted 30-day outcomes. Similar to the results described previously by Al-Refaie et al17 and Kennedy et al,18 the elderly (defined as older than 75 years) patients had significantly higher risk-adjusted perioperative morbidity (2.9- to 6.7-fold higher) and mortality (1.2- to 2.0-fold higher) than younger patients. Within colorectal surgery procedures, the following complications occurred significantly more frequently in the elderly population: SSI, pneumonia, unplanned or prolonged intubation, renal failure, urinary tract infection, stroke, cardiac arrest, myocardial infarction, overall morbidity, and mortality. In contrast, complications like dehiscence, deep venous thrombosis or pulmonary embolism, bleeding, and return to the operating room were not more frequent in the elderly patients undergoing colorectal surgery. The authors concluded that current quality measures need to be expanded to include complications that occur more commonly in the elderly population (eg, pulmonary and renal complications) rather than just the outcomes of SSI, deep venous thrombosis, and myocardial infarction addressed by the Surgical Care Improvement Project.
Outcomes Length of Stay Cohen et al21 used NSQIP from 2006 to 2007 to evaluate the variability of LOS after colorectal surgery, with the goal of identifying hospitals with outlying performance. The authors evaluated the relationship between LOS and postoperative
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168 complications by analyzing the following 3 groups: (1) patients without complications (86.8% of cohort), (2) patients with 1 or more complications (13.2%), and (3) partitioning by preoperative morbidity risk terciles (22.4%, 38.7%, and 60% of patients having complications). In general, LOS increased with higher complication rates. For example, the median LOS for patients without postoperative complications was 5 days, versus 12 days for patients with 1 or more postoperative complications. Similarly, the median LOS increased with predicted morbidity risk and was 5, 6, and 7 days for low, moderate, and high risk, respectively, of postoperative morbidity. The authors concluded that NSQIP can provide hospitals with risk-adjusted LOS measures that may ultimately be used to identify outlying performance with respect to the outcome of LOS. Stefanou et al22 used NSQIP from 2005 to 2009 to evaluate the outcome of LOS after colectomy, with an emphasis on evaluating the impact of surgical approach (laparoscopic vs open). The authors identified a cohort of 45,654 patients undergoing colectomy; 27.3% of the colectomies were performed laparoscopically. The median LOS was 5 days for laparoscopic colectomy and 8 days for open colectomy. Patients were identified as outliers if they had a LOS of ⬎75th percentile, which was 11 days; 27.9% of open colectomy patients were outliers, whereas only 9.2% of laparoscopic colectomy patients were outliers. Linear regression to predict LOS as the outcome demonstrated that open colectomy increased LOS by 1.8 days. Similarly, using logistic regression to predict outlier LOS status, open colectomy had significantly higher odds of prolonged LOS (OR: 3.8). The authors concluded that laparoscopic colectomy significantly decreased LOS in comparison with the open approach, while adjusting for other patient factors that may also influence LOS.
Postdischarge VTE Merkow et al23 used NSQIP to determine the rate of postdischarge VTE after cancer surgery. Using NSQIP from 2006 to 2008, the authors identified 44,656 patients undergoing surgery for cancer; within this cohort, 12,946 underwent colon cancer surgery and 2258 underwent rectal cancer surgery. The overall rate of VTE was 2.0% for colon cancer and 2.3% for rectal cancer. With respect to timing of VTE, 33.9% occurred after hospital discharge for colon cancer surgery and 23.2% occurred after hospital discharge for rectal cancer surgery. Factors associated with increased odds of postoperative VTE on multivariate analysis were age, cancer site, obesity, ascites, thrombocytosis, hypoalbuminemia, and operative time of ⬎2 hours. Patients undergoing colorectal cancer surgery had significantly higher odds (5.1 OR for colon cancer, 6.0 OR for rectal cancer) of VTE compared with those undergoing breast surgery. Of note, the cancer patients at highest risk for VTE after surgery were esophagogastric (OR: 9.3) and hepatopancreaticobiliary (OR: 7.8). The authors concluded that VTE occurs after hospital discharge in approximately 33% of patients undergoing cancer surgery, which raises the
question as to whether postdischarge pharmacologic prophylaxis should be considered for high-risk patients. Xenos et al24 also used NSQIP from 2005 to 2009 to evaluate the outcome of VTE after colorectal cancer surgery, with an emphasis on the association of intraoperative blood transfusion. A cohort of 21,943 patients undergoing colorectal cancer resection was identified; the 30-day rate of VTE was 2.0%, which is similar to the results discussed previously by Merkow et al.23 The rate of VTE increased as the number of units of transfused packed red blood cells increased (1.8% for 0 U, 3.7% for 1-2 U, 4.9% for 3-5 U, and 9.4% for ⱖ6 U). This finding was confirmed in multivariate analysis demonstrating that increasing intraoperative transfusion of packed red blood cells was associated with increased odds of VTE (1.4 OR for 1-2 U, 1.9 OR for 3-5 U, and 3.2 OR for ⱖ6 U). The authors concluded that intraoperative blood transfusion was a risk factor for postoperative VTE, which highlights the need for judicious use of blood transfusion along with aggressive measures to prevent VTE.
Return to Operating Room Ricciardi et al25 used NSQIP from 2005 to 2008 to identify a cohort of patients undergoing colorectal resection; 7.6% returned to the operating room within 30 days. During the same period, 5.4% of patients returned to the operating room within 30 days after undergoing all other noncolorectal surgery procedures. Patients undergoing total colectomy had the highest rate of return to the operating room (13.9%) compared with all other colorectal resections. On multivariate analysis, patients with diagnosis codes for cardiorespiratory illness (OR: 1.6), abdominal hernia (OR: 2.0), and colostomy (OR: 2.3) had significantly higher odds of return to the operating room than patients with a diagnosis code of neoplasm. In addition, return to the operating room was associated with the outcomes of prolonged LOS and increased mortality. The 30-day mortality rate in patients returned to the operating room after colorectal resection was 12.3% (vs 3.3% in patients who did not return to the operating room). The authors concluded that because return to the operating room is associated with negative outcomes, efforts should be made to minimize the need for reoperation. Unfortunately, the NSQIP data set does not include the reason for return to the operating room.
Risk Calculator for Colon and Rectal Surgery Cohen et al26 developed a morbidity and mortality risk calculator for colorectal surgery. A universal model with 15 variables was created to predict the outcomes of 30-day overall morbidity, serious morbidity, and mortality using patients who underwent colorectal surgery during 2006-2007; the results were validated using a cohort of patients who underwent colorectal surgery during 2005. During 2006-2007, 28,683 colorectal surgery procedures were performed, with the outcomes of 24.3% overall morbidity, 11.4% serious morbidity, and 3.9% mortality. The model included 3 pre-
NSQIP to study outcomes in colon and rectal surgery operative laboratory values (albumin, creatinine, partial thromboplastin time), 8 patient factors (age, ASA class, functional health status, BMI, and comorbidities of dyspnea, chronic obstructive pulmonary disease, disseminated cancer, and sepsis), and 4 surgery factors (indication for surgery, surgical extent, emergency surgery, and wound classification). This colorectal surgery risk calculator allows the surgeon to discuss a particular patient’s risk for morbidity and mortality based on individual patient data, which provides meaningful data to enhance the informed consent discussion, especially with respect to risks of surgery. In addition, the risk calculator allows the surgeon to discuss the hospital’s performance with respect to these outcomes as better-thanexpected, as-expected, and worse-than-expected. The development of this colorectal surgery risk calculator is an important step toward increasing the transparency of potential complications after surgery.
Limitations of NSQIP An evaluation of the impact of NSQIP on addressing quality and outcomes within colon and rectal surgery would not be complete without discussing potential limitations of using NSQIP data. First, the vast majority of articles using NSQIP suffer from selection bias because patients undergo a surgical intervention (eg, laparoscopic vs open surgery, primary resection and anastomosis for treatment of diverticulitis versus resection with end colostomy and Hartmann procedure) based on unmeasured clinical variables such as previous abdominal surgery or severity of diverticulitis. Specifically, with respect to colorectal cancer surgery, NSQIP does not collect relevant variables like tumor stage, tumor location, or receipt of neoadjuvant therapy. In addition with respect to studies evaluating laparoscopic surgery, NSQIP does not collect data on how the vascular pedicle or anastomosis was addressed, how much of the procedure was completed laparoscopically, and whether the procedure was converted to open. Second, there are issues of generalizability of results to non-ACSNSQIP hospitals because NSQIP is not a nationally representative sample of hospitals, although it does include a wide range of teaching and nonteaching hospitals. However, despite these limitations, NSQIP provides a unique resource for quality improvement efforts owing to the rigorous data collection and ability to provide risk-adjusted outcomes.
Areas for Future Research and Development A review of the current literature using NSQIP to evaluate outcomes in colon and rectal surgery highlights several areas for improvement. There is a need for development of both disease-specific and operation-specific variables. Examples of disease-specific variables within colorectal surgery include tumor location, stage, carcinoembryonic antigen level, and receipt of neoadjuvant chemoradiation therapy for colorectal cancer. Examples of operation-specific variables within colorectal surgery include level of anastomosis for rectal cancer
169 and type of anastomosis (eg, stapled vs handsewn). Additionally, the presence of physiologic recovery variables (eg, time to first bowel movement, time to feeding, and time to ambulation) after gastrointestinal surgery may help further adjust analyses for the outcome of LOS. Other variable gaps include measurement of patient socioeconomic status as well as surgeon training and experience. Finally, there is no specific outcome variable for anastomotic leak, which is an important outcome within the field of colorectal surgery. NSQIP does include organ/space SSI, which probably includes cases where an anastomotic leak has occurred, but granularity with respect to this outcome would be a useful end point for evaluation within colorectal surgery. With respect to future research within colorectal surgery, there is a notable absence of using NSQIP for evaluation of surgery in patients with ulcerative colitis. In addition, the vast majority of reviewed articles describe the outcomes after colorectal surgery as well as the impact of patient- or procedure-specific risk factors. More work is needed in the area of implementation of quality improvement interventions, including feedback of NSQIP data to address specific outcomes after colorectal surgery, such as SSI or postoperative pneumonia.
References 1. Ingraham AM, Cohen ME, Bilimoria KY, et al: Comparison of outcomes after laparoscopic versus open appendectomy for acute appendicitis at 222 ACS NSQIP hospitals. Surgery 148:625-635, 2010; discussion 635-637 2. Fleming FJ, Kim MJ, Messing S, et al: Balancing the risk of postoperative surgical infections: A multivariate analysis of factors associated with laparoscopic appendectomy from the NSQIP database. Ann Surg 252: 895-900, 2010 3. Kim MJ, Fleming FJ, Gunzler DD, et al: Laparoscopic appendectomy is safe and efficacious for the elderly: An analysis using the National Surgical Quality Improvement Project database. Surg Endosc 25:18021807, 2011 4. Tuggle KR, Ortega G, Bolorunduro OB, et al: Laparoscopic versus open appendectomy in complicated appendicitis: A review of the NSQIP database. J Surg Res 163:225-228, 2010 5. Page AJ, Pollock JD, Perez S, et al: Laparoscopic versus open appendectomy: An analysis of outcomes in 17,199 patients using ACS/NSQIP. J Gastrointest Surg 14:1955-1962, 2010 6. Gawlick U, Nirula R: Resection and primary anastomosis with proximal diversion instead of Hartmann’s: Evolving the management of diverticulitis using NSQIP data. J Trauma Acute Care Surg 72:807-814, 2012 7. Lee Y, Fleming FJ, Deeb AP, et al: A laparoscopic approach reduces short-term complications and length of stay following ileocolic resection in Crohn’s disease: An analysis of outcomes from the NSQIP database. Colorectal Dis 14:572-577, 2012 8. Russell MM, Read TE, Roberts PL, et al: Complications after rectal prolapse surgery: Does approach matter? Dis Colon Rectum 55:450458, 2012 9. Merkow RP, Bilimoria KY, McCarter MD, et al: Effect of body mass index on short-term outcomes after colectomy for cancer. J Am Coll Surg 208:53-61, 2009 10. Leichtle SW, Mouawad NJ, Lampman R, et al: Does preoperative anemia adversely affect colon and rectal surgery outcomes? J Am Coll Surg 212:187-194, 2011 11. Greenblatt DY, Rajamanickam V, Pugely AJ, et al: Short-term outcomes after laparoscopic-assisted proctectomy for rectal cancer: Results from the ACS NSQIP. J Am Coll Surg 212:844-854, 2011 12. Stewart DB, Hollenbeak C, Boltz M: Laparoscopic and open abdominoperineal resection for cancer: How patient selection and complications differ by approach. J Gastrointest Surg 15:1928-1938, 2011
170 13. Bilimoria KY, Bentrem DJ, Merkow RP, et al: Laparoscopic-assisted vs. open colectomy for cancer: Comparison of short-term outcomes from 121 hospitals. J Gastrointest Surg 12:2001-2009, 2008 14. McCloskey CA, Wilson MA, Hughes SJ, et al: Laparoscopic colorectal surgery is safe in the high-risk patient: A NSQIP risk-adjusted analysis. Surgery 142:594-597, 2007; discussion 597.e1-597.e2 15. Kiran RP, El-Gazzaz GH, Vogel JD, et al: Laparoscopic approach significantly reduces surgical site infections after colorectal surgery: Data from national surgical quality improvement program. J Am Coll Surg 211:232-238, 2010 16. Ingraham AM, Cohen ME, Bilimoria KY, et al: Comparison of hospital performance in nonemergency versus emergency colorectal operations at 142 hospitals. J Am Coll Surg 210:155-165, 2010 17. Al-Refaie WB, Parsons HM, Habermann EB, et al: Operative outcomes beyond 30-day mortality: Colorectal cancer surgery in oldest old. Ann Surg 253:947-952, 2011 18. Kennedy GD, Rajamanickam V, O’Connor ES, et al: Optimizing surgical care of colon cancer in the older adult population. Ann Surg 253: 508-514, 2011 19. Kwok AC, Lipsitz SR, Bader AM, et al: Are targeted preoperative risk prediction tools more powerful? A test of models for emergency colon surgery in the very elderly. J Am Coll Surg 213:220-225, 2011
M.M. Russell 20. Bentrem DJ, Cohen ME, Hynes DM, et al: Identification of specific quality improvement opportunities for the elderly undergoing gastrointestinal surgery. Arch Surg 144:1013-1020, 2009 21. Cohen ME, Bilimoria KY, Ko CY, et al: Variability in length of stay after colorectal surgery: Assessment of 182 hospitals in the national surgical quality improvement program. Ann Surg 250:901-907, 2009 22. Stefanou AJ, Reickert CA, Velanovich V, et al: Laparoscopic colectomy significantly decreases length of stay compared with open operation. Surg Endosc 26:144-148, 2012 23. Merkow RP, Bilimoria KY, McCarter MD, et al: Post-discharge venous thromboembolism after cancer surgery: Extending the case for extended prophylaxis. Ann Surg 254:131-137, 2011 24. Xenos ES, Vargas HD, Davenport DL: Association of blood transfusion and venous thromboembolism after colorectal cancer resection. Thromb Res 129:568-572, 2012 25. Ricciardi R, Roberts PL, Read TE, et al: How often do patients return to the operating room after colorectal resections? Colorectal Dis 14:515521, 2012 26. Cohen ME, Bilimoria KY, Ko CY, et al: Development of an American College of Surgeons National Surgery Quality Improvement Program: Morbidity and mortality risk calculator for colorectal surgery. J Am Coll Surg 208:1009-1016, 2009
T
he development of the American College of Surgeons’ (ACS) National Surgical Quality Improvement Program (NSQIP) has significantly enhanced our ability to evaluate outcomes after surgery. The goal of the current manuscript is to provide an overview of the types of research that have been performed using NSQIP within the field of colorectal surgery. Abstracts were identified through PubMed search (through October 2011) using the following key words: “NSQIP,” “National Surgery Quality Improvement Program,” “colon,” “rectal,” and “colorectal.” Abstracts were reviewed for content relevant to measuring quality and outcomes in colon and rectal surgery. A summary of published research using NSQIP to evaluate outcomes in colon and rectal surgery appears later in the text in addition to a discussion of NSQIP limitations and areas for future research.
Department of Surgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA. Address reprint requests to: Marcia McGory Russell, MD, Department of Surgical and Perioperative Care, VA Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Building 500, 6th Floor, 6 West, Mail Code 10H2, Los Angeles, CA 90073. E-mail: mrussell@mednet. ucla.edu
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1043-1489/$-see front matter Published by Elsevier Inc. http://dx.doi.org/10.1053/j.scrs.2012.07.006
Benign Disease Several studies examine outcomes after colorectal surgery for benign disease, including appendicitis, diverticulitis, inflammatory bowel disease, and rectal prolapse.
Appendicitis Ingraham et al1 compared outcomes after laparoscopic versus open appendectomy for acute appendicitis. A cohort of 32,683 patients undergoing appendectomy was identified using ACS-NSQIP from 2005 to 2008; most of the patients underwent laparoscopic (vs open) approach (76.4% vs 23.6%). Patients undergoing laparoscopic appendectomy had significantly lower odds of experiencing both overall morbidity (odds ratio [OR]: 0.6) and surgical site infection (SSI, OR: 0.6). In contrast, the subset of patients with complicated appendicitis who underwent laparoscopic appendectomy had higher odds (OR: 1.4) of developing organ space SSI. The authors concluded that laparoscopic appendectomy is associated with lower overall morbidity in selected patients. Fleming et al2 attempted to address the issue of increased organ space infection in patients undergoing laparoscopic appendectomy. Using NSQIP, 35,950 patients undergoing appendectomy were identified; 77% underwent laparoscopic appendectomy. Multivariate analysis revealed that laparoscopic appendectomy decreased the odds of incisional infection
NSQIP to study outcomes in colon and rectal surgery (OR: 0.4) but increased the odds of organ space infection (OR: 1.4). A unique feature of this study was using the multivariate model to calculate the probability of organ space infection based on specific clinical scenarios. For example, a 77-year-old male patient with clinical scenario of diabetes, smoker, sepsis, preoperative white blood cell count of 17, American Society of Anesthesiologists (ASA) class 4, emergency operation, wound class IV, and operative time of ⬎60 minutes had a predicted probability of organ space infection of 12.3% for laparoscopic approach and 8.9% for open approach. The authors concluded that laparoscopic appendectomy is associated with increased risk of organ space infection but decreased risk of incisional infection. Importantly, the degree of the increased risk for organ space infection is increased by patient-specific and procedure-specific risk factors, which may influence the choice of laparoscopic versus open approach for appendectomy. Multiple other articles use NSQIP to evaluate the benefits of laparoscopic appendectomy with respect to elderly patients, complicated appendicitis, and outcomes, including operative time, length of stay (LOS), and perioperative morbidity and mortality.3-5
Diverticulitis Gawlick et al6 used NSQIP to identify patients with perforated diverticulitis undergoing emergent operative intervention. Outcomes were compared by surgical intervention: primary colectomy with anastomosis and diverting loop ileostomy versus partial colectomy with end colostomy (ie, Hartmann procedure). A total of 2018 patients with perforated diverticulitis requiring surgery were identified from 2005 to 2008; the majority (83%) underwent Hartmann procedure. Using multivariate analysis, there was no significant difference between the 2 surgical procedures with respect to the odds of wound infection, organ space infection, wound dehiscence, return to the operating room, need for postoperative mechanical ventilation, sepsis, or death. A subgroup analysis of patients with dirty/infected wounds (vs contaminated wounds) revealed significantly higher odds of death with primary anastomosis and diverting loop ileostomy compared with Hartmann procedure (OR: 2.0). The authors concluded that primary resection and anastomosis with diverting loop ileostomy should be considered in selected patients owing to the decreased morbidity associated with loop ileostomy reversal in comparison with Hartmann reversal.
Inflammatory Bowel Disease Lee et al7 evaluated the outcomes of ileocolic resection for Crohn’s disease using NSQIP from 2005 to 2009. A total of 1917 patients undergoing ileocolic resection for Crohn’s disease were identified; 34% of the resections were performed laparoscopically. Patients undergoing laparoscopic ileocolic resection had significantly lower rates of both major (7.6% vs 14.5%) and minor (9.2% vs 12.7%) complications compared with those undergoing open ileocolic resection. These findings were confirmed on multivariate analysis, with laparoscopic approach demonstrating significantly lower odds of
165 both major (OR: 0.6) and minor (OR: 0.6) complications. The authors concluded that laparoscopic ileocolic resection for Crohn’s disease is safer than the open approach. Of note, none of the articles identified addressed outcomes for ulcerative colitis patients undergoing surgery.
Rectal Prolapse The author and her colleagues from the Lahey Clinic compared outcomes after transabdominal versus transperineal repair for rectal prolapse.8 They identified a cohort of 1485 patients undergoing rectal prolapse surgery using ACSNSQIP from 2005 to 2008. The abdominal approach for rectal prolapse had significantly higher rates of infectious (9.8% vs 3.7%) and overall (12.9% vs 7.6%) complications in comparison with the transperineal approach. Multivariate analysis demonstrated that ASA class 4 (OR: 6.4) and abdominal approach (OR: 2.3) were risk factors for overall complications, whereas ASA class 4 (OR: 7.5), body mass index (BMI) ⱖ25 (OR: 1.8), and abdominal approach (OR: 2.8) were risk factors for infectious complications. We concluded that patients with significant comorbidities (as measured by ASA class or high BMI) may be at higher risk for postoperative complications and should be considered for transperineal rather than abdominal approach.
Patient-Specific Risk Factors Body Mass Index Merkow et al9 evaluated the effect of BMI on short-term outcomes after colectomy for colon cancer using the ACS-NSQIP database. The authors identified 3202 patients who underwent colectomy for cancer in 2007. Using multivariate logistic regression, they evaluated the independent impact of BMI on specific complications (ie, SSI) as well as overall morbidity. Morbidly obese patients had significantly higher odds than normal-weight patients of superficial SSI (OR: 3.1), deep SSI (OR: 4.2), wound dehiscence (OR: 3.5), pulmonary embolus (OR: 7.0), and renal failure (OR: 2.8). In contrast, obese patients only experienced a higher risk of pulmonary embolus (OR: 5.1) in comparison with normal-weight patients. Finally, overweight patients experienced higher odds of both SSI (OR: 1.8) and pulmonary embolism (OR: 5.1) in comparison with normal-weight patients. With respect to overall morbidity, morbidly obese patients had a 1.7-fold higher odds of any perioperative complication after colectomy for cancer, whereas overweight patients had a 1.3-fold higher odds, in comparison with normal-weight patients. The authors concluded that obesity does not appear to impact mortality or other types of complications after colon cancer surgery, like other infections (ie, pneumonia, urinary tract infection, sepsis), prolonged intubation, myocardial infarction, stroke, or reoperation.
Preoperative Anemia Leichtle et al10 used NSQIP from 2005 to 2008 to determine whether preoperative anemia adversely affects outcomes in colon and rectal surgery. The authors looked at the outcomes
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166 of increased LOS in addition to a composite outcome, including myocardial infarction, stroke, progressive renal insufficiency, and death within 30 days of surgery. Anemia was classified into 4 categories based on preoperative hematocrit: severe (21%-25%), moderate (26%-29%), mild (30%-37%), and no anemia (ⱖ38%). The distribution of patients undergoing colon and rectal surgery by anemia group was as follows: 52.6% no anemia, 38.7% mild, 7.4% moderate, and 1.3% severe. Using logistic regression analysis with propensity score matching, patients with anemia had significantly higher odds of both the composite outcome (1.8 higher odds for severe anemia, 2.2 for moderate, and 1.5 for mild) and LOS (3 days for severe anemia, 1.9 days for moderate, and 0.6 days for mild) compared with patients without anemia. The authors concluded that preoperative anemia is an independent risk factor for postoperative complications as well as prolonged hospital stay.
Procedure-Specific Risk Factors Laparoscopy Greenblatt et al11 evaluated short-term outcomes after laparoscopic-assisted proctectomy for rectal cancer using the ACS-NSQIP database. From 2005 to 2009, 5420 patients were identified who underwent surgery for rectal cancer; 19% of these patients underwent laparoscopic-assisted proctectomy. The open proctectomy group had a significantly higher 30-day complication rate than the laparoscopic-assisted proctectomy group (28.8% vs 20.5%, P ⬍ 0.0001). Specifically, the open proctectomy group had higher rates of superficial SSI, sepsis, respiratory complications, renal failure, and venous thromboembolism (VTE) when compared with the laparoscopic-assisted proctectomy group. In addition, the patients undergoing laparoscopic-assisted proctectomy had lower rates of intraoperative blood transfusion (4.3% vs 12.3%, P ⬍ 0.0001) and shorter LOS (median 5 vs 7 days, P ⬍ 0.0001). On multivariate analysis to identify predictors of morbidity, open proctectomy had significantly higher odds of 30-day morbidity in comparison with laparoscopic-assisted proctectomy (OR: 1.4). The authors concluded that laparoscopic-assisted proctectomy was associated with shorter LOS and decreased 30-day morbidity compared with open proctectomy. Stewart et al12 evaluated laparoscopic versus open abdominoperineal resection (APR) using 2005-2008 NSQIP data. The goal was to evaluate variables that influenced the type of surgical approach as well as identify predictors of postoperative complications. A total of 1340 patients were identified; 10.7% underwent laparoscopic APR. Factors associated with significantly increased odds of undergoing laparoscopic APR were female gender (OR: 1.6), non-Caucasian race (1.5), and BMI ⬍25 (OR: 1.5). With respect to postoperative complications, there was no significant difference in complication rates by surgical approach (open APR: 64%; laparoscopic APR: 53%). Predictors of complications after open APR were tobacco use (OR: 1.8), history of cerebrovascular accident (OR: 2.4), and ⬎10% weight loss before surgery (OR: 1.6).
The only predictor of complications after laparoscopic APR was systemic hypertension (OR: 2.5). The authors concluded that few patients are being offered laparoscopic APR due to surgeon preference rather than patient-specific factors, as the overall complication rate is similar between laparoscopic and open APR. Bilmoria et al13 used NSQIP to compare short-term outcomes of laparoscopic-assisted versus open colectomy for colon cancer. During 2005-2006, the authors identified 3059 patients who underwent colectomy for treatment of colon cancer; 27.4% underwent laparoscopic-assisted colectomy. Patients undergoing laparoscopic-assisted colectomy had lower rates of any adverse event (14.6% vs 21.7% in open colectomy), especially infectious complications like SSI (9.1% vs 11.8%), urinary tract infection (1.9% vs 3.2%), and pneumonia (1.8% vs 3.4%). The rate of wound disruption/ dehiscence was also notably lower in these patients (0.5% vs 1.5%). These results were confirmed on multivariate analysis because patients undergoing open colectomy had higher odds of any adverse event (OR: 1.5) as well as specific complications like SSI (OR: 1.3), wound disruption/dehiscence (OR: 3.0), pneumonia (OR: 1.8), and urinary tract infection (OR: 1.8). The authors concluded that laparoscopic-assisted colectomy for colon cancer was associated with lower postoperative morbidity, especially for infectious complications. McCloskey et al14 used NSQIP to evaluate laparoscopic colorectal surgery in the high-risk patient, as defined by a NSQIP-predicted complication rate of ⬎15%. The authors identified consecutive patients undergoing laparoscopic or open colectomy from 2002 to 2004 and used NSQIP to classify these patients as high or low risk based on the NSQIPpredicted complication rate for each patient. Forty-five highrisk patients were identified, and the patients undergoing laparoscopic colectomy had significantly lower major complications than those undergoing open colectomy (4% vs 41%). The LOS was also significantly shorter in the laparoscopic group (5 vs 8 days). The authors concluded that laparoscopic colorectal surgery is safe in patients predicted to have high postoperative morbidity and mortality. Kiran et al15 used NSQIP from 2006 to 2007 to evaluate the outcome of SSI between patients undergoing laparoscopic and open colorectal surgery. A total of 10,979 patients underwent colorectal surgery during this period; 31.1% of the cases were performed laparoscopically. The overall rate of SSI was 14% and was significantly higher in the open compared with the laparoscopic group (16.1% vs 9.5%). Multivariate analysis revealed that age; open surgical approach; ASA score of ⱖ3; smoking; diabetes; operative time of ⬎180 minutes; diagnoses of appendicitis, diverticulitis, or regional enteritis (Crohn’s disease); and operations involving the rectum (coloproctostomy, Hartmann procedure, and low pelvic anastomosis) were associated with significantly higher odds of SSI. The authors concluded that laparoscopy is independently associated with a lower rate of SSI in colorectal surgery.
Emergency Surgery Ingraham et al16 used NSQIP from 2005 to 2007 to compare hospital performance in nonemergency versus emergency
NSQIP to study outcomes in colon and rectal surgery colorectal operations. The authors identified a cohort of 25,710 patients undergoing nonemergency colorectal resection and 5083 undergoing emergency colorectal resection. Both morbidity (48% emergency vs 23.9% nonemergency) and mortality (15.3% emergency vs 1.9% nonemergency) rates were significantly higher in the group of patients undergoing emergency surgery. Of note, a hospital’s observed/expected ratios after nonemergency and emergency colorectal operations were weakly correlated for morbidity (Pearson correlation coefficient: 0.3) and minimally correlated for mortality (Pearson correlation coefficient: 0.2). In addition, hospital rankings changed when comparing both morbidity and mortality after nonemergency versus emergency colorectal operations. The authors concluded that hospitals with good outcomes after nonemergency colorectal operations do not necessarily have comparable outcomes after emergency colorectal operations, which may identify an area for quality improvement.
Specific Patient Population: Elderly Al-Refaie et al17 used NSQIP to compare outcomes after colorectal cancer surgery in the oldest-old (ⱖ80 years) with a younger cohort (40-55 years). The oldest-old experienced significantly higher rates of 30-day mortality (6% vs ⬍1%) and major complications (21% vs 14%) in comparison with younger patients. The oldest-old also had significantly longer LOS after both open and laparoscopic procedures in comparison with younger patients. The authors used multivariate analysis to identify predictors of 5 outcomes: (1) 30-day mortality, (2) major complications after open colorectal cancer surgery, (3) major complications after laparoscopic colorectal cancer surgery, (4) prolonged LOS after open colorectal cancer surgery, and (5) prolonged LOS after laparoscopic colorectal cancer surgery. The following variables were predictive of increased odds of all 5 outcomes: age ⱖ80 years, ASA score of 3 or 4, and ⱖ2 U of red blood cell transfusion. The authors concluded that the effects of older age not only influence mortality but also other outcomes like morbidity and LOS. Kennedy et al18 sought to optimize surgical care for older patients with colon cancer. They used NSQIP from 2005 to 2008 to identify 5914 patients aged 65 years or older who underwent surgery for colon cancer. The outcome of interest was 30-day morbidity or 30-day mortality, and the authors had a special interest in evaluating the impact of laparoscopic versus open surgery for elderly patients with colon cancer. To statistically compensate for nonrandom assignment to laparoscopic versus open surgery, they used propensity score matching. Elderly patients undergoing laparoscopic surgery had significantly lower rates of postoperative morbidity (16.1% vs 25.4%) and mortality (2.1% vs 3.7%) compared with those undergoing open surgery. Factors predictive of both 30-day morbidity and 30-day mortality included open surgery, age ⬎75 years, totally/partially dependent functional status, presence of ascites, and ASA class 2 or 3. The
167 authors concluded that expanding laparoscopic procedures in the elderly population may improve outcomes for patients with colon cancer. Kwok et al19 sought to develop a preoperative risk prediction tool for patients aged 80 years or older needing an emergency colectomy. The prediction tool was created using ACSNSQIP data from 2007 to 2008. The 8 variables most significantly associated with mortality in the elderly population needing emergency colectomy were as follows: age 80-89 years, totally dependent functional status, history of chronic obstructive pulmonary disease, history of congestive heart failure, metastatic cancer, preoperative steroids, systemic inflammatory response syndrome, and creatinine ⬎1.5 mg/dL. This targeted risk tool correctly predicted mortality 56% of the time (when there was 80% specificity), which was better than prediction of mortality using the ASA score, the Surgical Risk Scale (uses ASA score along with urgency and complexity of operation), and the ACS Colorectal Surgery Risk Calculator, described later in the text. The authors concluded that because their targeted risk prediction tool has better discriminating power than other more generic risk prediction tools, more specialized risk assessment tools may need to be developed for specific procedures as well as specific patient populations, like the elderly population. Bentrem et al20 used NSQIP to identify specific quality improvement opportunities for elderly patients undergoing gastrointestinal surgery. They used NSQIP from 2005 to 2006 to identify patients undergoing upper gastrointestinal tract, hepatobiliary or pancreatic, and colorectal surgery and evaluated risk-adjusted 30-day outcomes. Similar to the results described previously by Al-Refaie et al17 and Kennedy et al,18 the elderly (defined as older than 75 years) patients had significantly higher risk-adjusted perioperative morbidity (2.9- to 6.7-fold higher) and mortality (1.2- to 2.0-fold higher) than younger patients. Within colorectal surgery procedures, the following complications occurred significantly more frequently in the elderly population: SSI, pneumonia, unplanned or prolonged intubation, renal failure, urinary tract infection, stroke, cardiac arrest, myocardial infarction, overall morbidity, and mortality. In contrast, complications like dehiscence, deep venous thrombosis or pulmonary embolism, bleeding, and return to the operating room were not more frequent in the elderly patients undergoing colorectal surgery. The authors concluded that current quality measures need to be expanded to include complications that occur more commonly in the elderly population (eg, pulmonary and renal complications) rather than just the outcomes of SSI, deep venous thrombosis, and myocardial infarction addressed by the Surgical Care Improvement Project.
Outcomes Length of Stay Cohen et al21 used NSQIP from 2006 to 2007 to evaluate the variability of LOS after colorectal surgery, with the goal of identifying hospitals with outlying performance. The authors evaluated the relationship between LOS and postoperative
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168 complications by analyzing the following 3 groups: (1) patients without complications (86.8% of cohort), (2) patients with 1 or more complications (13.2%), and (3) partitioning by preoperative morbidity risk terciles (22.4%, 38.7%, and 60% of patients having complications). In general, LOS increased with higher complication rates. For example, the median LOS for patients without postoperative complications was 5 days, versus 12 days for patients with 1 or more postoperative complications. Similarly, the median LOS increased with predicted morbidity risk and was 5, 6, and 7 days for low, moderate, and high risk, respectively, of postoperative morbidity. The authors concluded that NSQIP can provide hospitals with risk-adjusted LOS measures that may ultimately be used to identify outlying performance with respect to the outcome of LOS. Stefanou et al22 used NSQIP from 2005 to 2009 to evaluate the outcome of LOS after colectomy, with an emphasis on evaluating the impact of surgical approach (laparoscopic vs open). The authors identified a cohort of 45,654 patients undergoing colectomy; 27.3% of the colectomies were performed laparoscopically. The median LOS was 5 days for laparoscopic colectomy and 8 days for open colectomy. Patients were identified as outliers if they had a LOS of ⬎75th percentile, which was 11 days; 27.9% of open colectomy patients were outliers, whereas only 9.2% of laparoscopic colectomy patients were outliers. Linear regression to predict LOS as the outcome demonstrated that open colectomy increased LOS by 1.8 days. Similarly, using logistic regression to predict outlier LOS status, open colectomy had significantly higher odds of prolonged LOS (OR: 3.8). The authors concluded that laparoscopic colectomy significantly decreased LOS in comparison with the open approach, while adjusting for other patient factors that may also influence LOS.
Postdischarge VTE Merkow et al23 used NSQIP to determine the rate of postdischarge VTE after cancer surgery. Using NSQIP from 2006 to 2008, the authors identified 44,656 patients undergoing surgery for cancer; within this cohort, 12,946 underwent colon cancer surgery and 2258 underwent rectal cancer surgery. The overall rate of VTE was 2.0% for colon cancer and 2.3% for rectal cancer. With respect to timing of VTE, 33.9% occurred after hospital discharge for colon cancer surgery and 23.2% occurred after hospital discharge for rectal cancer surgery. Factors associated with increased odds of postoperative VTE on multivariate analysis were age, cancer site, obesity, ascites, thrombocytosis, hypoalbuminemia, and operative time of ⬎2 hours. Patients undergoing colorectal cancer surgery had significantly higher odds (5.1 OR for colon cancer, 6.0 OR for rectal cancer) of VTE compared with those undergoing breast surgery. Of note, the cancer patients at highest risk for VTE after surgery were esophagogastric (OR: 9.3) and hepatopancreaticobiliary (OR: 7.8). The authors concluded that VTE occurs after hospital discharge in approximately 33% of patients undergoing cancer surgery, which raises the
question as to whether postdischarge pharmacologic prophylaxis should be considered for high-risk patients. Xenos et al24 also used NSQIP from 2005 to 2009 to evaluate the outcome of VTE after colorectal cancer surgery, with an emphasis on the association of intraoperative blood transfusion. A cohort of 21,943 patients undergoing colorectal cancer resection was identified; the 30-day rate of VTE was 2.0%, which is similar to the results discussed previously by Merkow et al.23 The rate of VTE increased as the number of units of transfused packed red blood cells increased (1.8% for 0 U, 3.7% for 1-2 U, 4.9% for 3-5 U, and 9.4% for ⱖ6 U). This finding was confirmed in multivariate analysis demonstrating that increasing intraoperative transfusion of packed red blood cells was associated with increased odds of VTE (1.4 OR for 1-2 U, 1.9 OR for 3-5 U, and 3.2 OR for ⱖ6 U). The authors concluded that intraoperative blood transfusion was a risk factor for postoperative VTE, which highlights the need for judicious use of blood transfusion along with aggressive measures to prevent VTE.
Return to Operating Room Ricciardi et al25 used NSQIP from 2005 to 2008 to identify a cohort of patients undergoing colorectal resection; 7.6% returned to the operating room within 30 days. During the same period, 5.4% of patients returned to the operating room within 30 days after undergoing all other noncolorectal surgery procedures. Patients undergoing total colectomy had the highest rate of return to the operating room (13.9%) compared with all other colorectal resections. On multivariate analysis, patients with diagnosis codes for cardiorespiratory illness (OR: 1.6), abdominal hernia (OR: 2.0), and colostomy (OR: 2.3) had significantly higher odds of return to the operating room than patients with a diagnosis code of neoplasm. In addition, return to the operating room was associated with the outcomes of prolonged LOS and increased mortality. The 30-day mortality rate in patients returned to the operating room after colorectal resection was 12.3% (vs 3.3% in patients who did not return to the operating room). The authors concluded that because return to the operating room is associated with negative outcomes, efforts should be made to minimize the need for reoperation. Unfortunately, the NSQIP data set does not include the reason for return to the operating room.
Risk Calculator for Colon and Rectal Surgery Cohen et al26 developed a morbidity and mortality risk calculator for colorectal surgery. A universal model with 15 variables was created to predict the outcomes of 30-day overall morbidity, serious morbidity, and mortality using patients who underwent colorectal surgery during 2006-2007; the results were validated using a cohort of patients who underwent colorectal surgery during 2005. During 2006-2007, 28,683 colorectal surgery procedures were performed, with the outcomes of 24.3% overall morbidity, 11.4% serious morbidity, and 3.9% mortality. The model included 3 pre-
NSQIP to study outcomes in colon and rectal surgery operative laboratory values (albumin, creatinine, partial thromboplastin time), 8 patient factors (age, ASA class, functional health status, BMI, and comorbidities of dyspnea, chronic obstructive pulmonary disease, disseminated cancer, and sepsis), and 4 surgery factors (indication for surgery, surgical extent, emergency surgery, and wound classification). This colorectal surgery risk calculator allows the surgeon to discuss a particular patient’s risk for morbidity and mortality based on individual patient data, which provides meaningful data to enhance the informed consent discussion, especially with respect to risks of surgery. In addition, the risk calculator allows the surgeon to discuss the hospital’s performance with respect to these outcomes as better-thanexpected, as-expected, and worse-than-expected. The development of this colorectal surgery risk calculator is an important step toward increasing the transparency of potential complications after surgery.
Limitations of NSQIP An evaluation of the impact of NSQIP on addressing quality and outcomes within colon and rectal surgery would not be complete without discussing potential limitations of using NSQIP data. First, the vast majority of articles using NSQIP suffer from selection bias because patients undergo a surgical intervention (eg, laparoscopic vs open surgery, primary resection and anastomosis for treatment of diverticulitis versus resection with end colostomy and Hartmann procedure) based on unmeasured clinical variables such as previous abdominal surgery or severity of diverticulitis. Specifically, with respect to colorectal cancer surgery, NSQIP does not collect relevant variables like tumor stage, tumor location, or receipt of neoadjuvant therapy. In addition with respect to studies evaluating laparoscopic surgery, NSQIP does not collect data on how the vascular pedicle or anastomosis was addressed, how much of the procedure was completed laparoscopically, and whether the procedure was converted to open. Second, there are issues of generalizability of results to non-ACSNSQIP hospitals because NSQIP is not a nationally representative sample of hospitals, although it does include a wide range of teaching and nonteaching hospitals. However, despite these limitations, NSQIP provides a unique resource for quality improvement efforts owing to the rigorous data collection and ability to provide risk-adjusted outcomes.
Areas for Future Research and Development A review of the current literature using NSQIP to evaluate outcomes in colon and rectal surgery highlights several areas for improvement. There is a need for development of both disease-specific and operation-specific variables. Examples of disease-specific variables within colorectal surgery include tumor location, stage, carcinoembryonic antigen level, and receipt of neoadjuvant chemoradiation therapy for colorectal cancer. Examples of operation-specific variables within colorectal surgery include level of anastomosis for rectal cancer
169 and type of anastomosis (eg, stapled vs handsewn). Additionally, the presence of physiologic recovery variables (eg, time to first bowel movement, time to feeding, and time to ambulation) after gastrointestinal surgery may help further adjust analyses for the outcome of LOS. Other variable gaps include measurement of patient socioeconomic status as well as surgeon training and experience. Finally, there is no specific outcome variable for anastomotic leak, which is an important outcome within the field of colorectal surgery. NSQIP does include organ/space SSI, which probably includes cases where an anastomotic leak has occurred, but granularity with respect to this outcome would be a useful end point for evaluation within colorectal surgery. With respect to future research within colorectal surgery, there is a notable absence of using NSQIP for evaluation of surgery in patients with ulcerative colitis. In addition, the vast majority of reviewed articles describe the outcomes after colorectal surgery as well as the impact of patient- or procedure-specific risk factors. More work is needed in the area of implementation of quality improvement interventions, including feedback of NSQIP data to address specific outcomes after colorectal surgery, such as SSI or postoperative pneumonia.
References 1. Ingraham AM, Cohen ME, Bilimoria KY, et al: Comparison of outcomes after laparoscopic versus open appendectomy for acute appendicitis at 222 ACS NSQIP hospitals. Surgery 148:625-635, 2010; discussion 635-637 2. Fleming FJ, Kim MJ, Messing S, et al: Balancing the risk of postoperative surgical infections: A multivariate analysis of factors associated with laparoscopic appendectomy from the NSQIP database. Ann Surg 252: 895-900, 2010 3. Kim MJ, Fleming FJ, Gunzler DD, et al: Laparoscopic appendectomy is safe and efficacious for the elderly: An analysis using the National Surgical Quality Improvement Project database. Surg Endosc 25:18021807, 2011 4. Tuggle KR, Ortega G, Bolorunduro OB, et al: Laparoscopic versus open appendectomy in complicated appendicitis: A review of the NSQIP database. J Surg Res 163:225-228, 2010 5. Page AJ, Pollock JD, Perez S, et al: Laparoscopic versus open appendectomy: An analysis of outcomes in 17,199 patients using ACS/NSQIP. J Gastrointest Surg 14:1955-1962, 2010 6. Gawlick U, Nirula R: Resection and primary anastomosis with proximal diversion instead of Hartmann’s: Evolving the management of diverticulitis using NSQIP data. J Trauma Acute Care Surg 72:807-814, 2012 7. Lee Y, Fleming FJ, Deeb AP, et al: A laparoscopic approach reduces short-term complications and length of stay following ileocolic resection in Crohn’s disease: An analysis of outcomes from the NSQIP database. Colorectal Dis 14:572-577, 2012 8. Russell MM, Read TE, Roberts PL, et al: Complications after rectal prolapse surgery: Does approach matter? Dis Colon Rectum 55:450458, 2012 9. Merkow RP, Bilimoria KY, McCarter MD, et al: Effect of body mass index on short-term outcomes after colectomy for cancer. J Am Coll Surg 208:53-61, 2009 10. Leichtle SW, Mouawad NJ, Lampman R, et al: Does preoperative anemia adversely affect colon and rectal surgery outcomes? J Am Coll Surg 212:187-194, 2011 11. Greenblatt DY, Rajamanickam V, Pugely AJ, et al: Short-term outcomes after laparoscopic-assisted proctectomy for rectal cancer: Results from the ACS NSQIP. J Am Coll Surg 212:844-854, 2011 12. Stewart DB, Hollenbeak C, Boltz M: Laparoscopic and open abdominoperineal resection for cancer: How patient selection and complications differ by approach. J Gastrointest Surg 15:1928-1938, 2011
170 13. Bilimoria KY, Bentrem DJ, Merkow RP, et al: Laparoscopic-assisted vs. open colectomy for cancer: Comparison of short-term outcomes from 121 hospitals. J Gastrointest Surg 12:2001-2009, 2008 14. McCloskey CA, Wilson MA, Hughes SJ, et al: Laparoscopic colorectal surgery is safe in the high-risk patient: A NSQIP risk-adjusted analysis. Surgery 142:594-597, 2007; discussion 597.e1-597.e2 15. Kiran RP, El-Gazzaz GH, Vogel JD, et al: Laparoscopic approach significantly reduces surgical site infections after colorectal surgery: Data from national surgical quality improvement program. J Am Coll Surg 211:232-238, 2010 16. Ingraham AM, Cohen ME, Bilimoria KY, et al: Comparison of hospital performance in nonemergency versus emergency colorectal operations at 142 hospitals. J Am Coll Surg 210:155-165, 2010 17. Al-Refaie WB, Parsons HM, Habermann EB, et al: Operative outcomes beyond 30-day mortality: Colorectal cancer surgery in oldest old. Ann Surg 253:947-952, 2011 18. Kennedy GD, Rajamanickam V, O’Connor ES, et al: Optimizing surgical care of colon cancer in the older adult population. Ann Surg 253: 508-514, 2011 19. Kwok AC, Lipsitz SR, Bader AM, et al: Are targeted preoperative risk prediction tools more powerful? A test of models for emergency colon surgery in the very elderly. J Am Coll Surg 213:220-225, 2011
M.M. Russell 20. Bentrem DJ, Cohen ME, Hynes DM, et al: Identification of specific quality improvement opportunities for the elderly undergoing gastrointestinal surgery. Arch Surg 144:1013-1020, 2009 21. Cohen ME, Bilimoria KY, Ko CY, et al: Variability in length of stay after colorectal surgery: Assessment of 182 hospitals in the national surgical quality improvement program. Ann Surg 250:901-907, 2009 22. Stefanou AJ, Reickert CA, Velanovich V, et al: Laparoscopic colectomy significantly decreases length of stay compared with open operation. Surg Endosc 26:144-148, 2012 23. Merkow RP, Bilimoria KY, McCarter MD, et al: Post-discharge venous thromboembolism after cancer surgery: Extending the case for extended prophylaxis. Ann Surg 254:131-137, 2011 24. Xenos ES, Vargas HD, Davenport DL: Association of blood transfusion and venous thromboembolism after colorectal cancer resection. Thromb Res 129:568-572, 2012 25. Ricciardi R, Roberts PL, Read TE, et al: How often do patients return to the operating room after colorectal resections? Colorectal Dis 14:515521, 2012 26. Cohen ME, Bilimoria KY, Ko CY, et al: Development of an American College of Surgeons National Surgery Quality Improvement Program: Morbidity and mortality risk calculator for colorectal surgery. J Am Coll Surg 208:1009-1016, 2009