Elise H. Lawson

Risk Factors for Superficial vs Deep/Organ-Space Surgical Site Infections: Implications for Quality Improvement Initiatives

IMPORTANCE Surgical site infections (SSIs) are the focus of numerous quality improvement initiatives because they are a common and costly cause of potentially preventable patient morbidity. Superficial and deep/organ-space SSIs differ in terms of anatomical location and clinical severity. OBJECTIVE To identify risk factors that are uniquely predictive of superficial vs deep/organ-space SSIs occurring after colectomy procedures. DESIGN Retrospective cohort study. SETTING American College of Surgeons National Surgical Quality Improvement Program. PARTICIPANTS Patients undergoing colectomy procedures in 2011 were identified by Current Procedural Terminology codes. INTERVENTION Colectomy procedures. MAIN OUTCOMES AND MEASURES We compared rates of superficial SSI and deep/organ-space SSI associated with perioperative variables of interest: demographics; preoperative clinical severity, risk factors, and comorbidities and variables related to the hospitalization or procedure. Hierarchical multivariable logistic regression models were developed to identify risk-adjusted predictors of each SSI type. RESULTS Among 27 011 patients identified from 305 hospitals, 6.2% developed a superficial SSI and 4.7% developed a deep/organ-space SSI. Risk factors common to the occurrence of both SSI types were identified: open surgery (vs laparoscopic) and current smoker. Risk factors with differential effects on each SSI type included specific postoperative diagnoses, disseminated cancer, and irradiation therapy, which were all associated with increased odds of deep/organ-space SSI only. The graded relationship between increasing body mass index and SSI occurrence appeared to be stronger for superficial SSI. CONCLUSIONS AND RELEVANCE Risk factors for superficial SSI and deep/organ-space SSI vary in terms of magnitude and significance, suggesting that these SSI types are somewhat different disease processes. Groups interested in preventing SSIs might improve success by considering these SSI types independently for root-cause analyses and development of best practices and interventions.

The appropriateness method has acceptable reliability and validity for assessing overuse and underuse of surgical procedures

OBJECTIVE To summarize the findings of methodological studies on the RAND/University of California Los Angeles (RAND/UCLA) appropriateness method, which was developed to assess if variation in the use of surgical procedures is because of overuse and/or underuse. STUDY DESIGN AND SETTING A MEDLINE literature search was performed. Studies were included if they assessed the reliability or validity of the RAND/UCLA appropriateness method for a surgical procedure or the effect of altering panelist composition or eliminating in-person discussion between rating rounds. Information was abstracted on procedure, study design, and findings. RESULTS One thousand six hundred one titles were identified, and 37 met the inclusion criteria. The test-retest reliability is good to very good (kappa, 0.64-0.81) for total knee and hip joint replacement, coronary artery bypass grafting (CABG), and carotid endarterectomy (CEA). The interpanel reliability is moderate to very good (kappa, 0.52-0.83) for CABG and hysterectomy. Construct validity has been demonstrated by comparing the appropriateness method with guidelines and/or evidence-based approaches for endoscopy, colonoscopy, CABG, hysterectomy, and CEA. Predictive validity has been studied for cardiac revascularization, in which concordance with appropriateness classification is associated with better clinical outcomes. CONCLUSION Our findings support use of the appropriateness method to assess variation in the rates of the procedures studied by identifying overuse and underuse. Further methodological research should be conducted as appropriateness criteria are developed and implemented for a broader range of procedures.

Relationship Between Hospital Performance on a Patient Satisfaction Survey and Surgical Quality

IMPORTANCE The Centers for Medicare and Medicaid Services include patient experience as a core component of its Value-Based Purchasing program, which ties financial incentives to hospital performance on a range of quality measures. However, it remains unclear whether patient satisfaction is an accurate marker of high-quality surgical care. OBJECTIVE To determine whether hospital performance on a patient satisfaction survey is associated with objective measures of surgical quality. DESIGN, SETTING, AND PARTICIPANTS Retrospective observational study of participating American College of Surgeons National Surgical Quality Improvement Project (ACS NSQIP) hospitals. We used data from a linked database of Medicare inpatient claims, ACS NSQIP, the American Hospital Association annual survey, and Hospital Compare from December 2, 2004, through December 31, 2008. A total of 103 866 patients older than 65 years undergoing inpatient surgery were included. Hospitals were grouped by quartile based on their performance on the Hospital Consumer Assessment of Healthcare Providers and Systems survey. Controlling for preoperative risk factors, we created hierarchical logistic regression models to predict the occurrence of adverse postoperative outcomes based on a hospitals patient satisfaction scores. MAIN OUTCOMES AND MEASURES Thirty-day postoperative mortality, major and minor complications, failure to rescue, and hospital readmission. RESULTS Of the 180 hospitals, the overall mean patient satisfaction score was 68.0% (first quartile mean, 58.7%; fourth quartile mean, 76.7%). Compared with patients treated at hospitals in the lowest quartile, those at the highest quartile had significantly lower risk-adjusted odds of death (odds ratio = 0.85; 95% CI, 0.73-0.99), failure to rescue (odds ratio = 0.82; 95% CI, 0.70-0.96), and minor complication (odds ratio = 0.87; 95% CI, 0.75-0.99). This translated to relative risk reductions of 11.1% (P = .04), 12.6% (P = .02), and 11.5% (P = .04), respectively. No significant relationship was noted between patient satisfaction and either major complication or hospital readmission. CONCLUSIONS AND RELEVANCE Using a national sample of hospitals, we demonstrated a significant association between patient satisfaction scores and several objective measures of surgical quality. Our findings suggest that payment policies that incentivize better patient experience do not require hospitals to sacrifice performance on other quality measures.

Linkage of a clinical surgical registry with Medicare inpatient claims data using indirect identifiers

BACKGROUND A variety of data sources are available for measuring the quality of health care. Linking records from different sources can create unique and powerful databases that can be used to evaluate clinically relevant questions and direct health care policy. The objective of this study was to develop and validate a deterministic linkage algorithm that uses indirect patient identifiers to reliably match records from a surgical clinical registry with Medicare inpatient claims data. METHODS Patient records from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP), years 2005-2008, were linked to claims data in the Medicare Provider Analysis and Review file (MedPAR) by the use of a deterministic linkage algorithm and the following indirect patient identifiers: hospital, age, sex, diagnosis, procedure and dates of admission, discharge, and procedure. We validated the linkage procedure by systematically reviewing subsets of matched and unmatched records and by determining agreement on patient-level coding of inpatient mortality. RESULTS Of the 150,454 records in ACS-NSQIP eligible for matching, 80.5% were linked to a MedPAR record. This percentage is within the expected match range given the estimated percentage of ACS-NSQIP patients likely to be Medicare beneficiaries. Systematic checks revealed no evidence of bias in the linkage procedure and there was excellent agreement on patient-level coding of mortality (kappa 0.969). The final linked database contained 121,070 patient records from 217 hospitals. CONCLUSION This study demonstrates the feasibility and validity of a method for linking 2 data sources without direct personal identifiers. As clinical registries and other data sources continue to proliferate, linkage algorithms such as described here will be critical for quality measurement purposes.

Validity and Feasibility of the American College of Surgeons Colectomy Composite Outcome Quality Measure.

Objective: To develop a reliable, robust, parsimonious, risk-adjusted 30-day composite colectomy outcome measure. Background: A fundamental aspect in the pursuit of high-quality care is the development of valid and reliable performance measures in surgery. Colon resection is associated with appreciable morbidity and mortality and therefore is an ideal quality improvement target. Methods: From 2010 American College of Surgeons National Surgical Quality Improvement Program data, patients were identified who underwent colon resection for any indication. A composite outcome of death or any serious morbidity within 30 days of the index operation was established. A 6-predictor, parsimonious model was developed and compared with a more complex model with more variables. National caseload requirements were calculated on the basis of increasing reliability thresholds. Results: From 255 hospitals, 22,346 patients were accrued who underwent a colon resection in 2010, most commonly for neoplasm (46.7%). A mortality or serious morbidity event occurred in 4461 patients (20.0%). At the hospital level, the median composite event rate was 20.7% (interquartile range: 15.8%–26.3%). The parsimonious model performed similarly to the full model (Akaike information criterion: 19,411 vs 18,988), and hospital-level performance comparisons were highly correlated (R = 0.97). At a reliability threshold of 0.4, 56 annual colon resections would be required and achievable at an estimated 42% of US and 69% of American College of Surgeons National Surgical Quality Improvement Program hospitals. This 42% of US hospitals performed approximately 84% of all colon resections in the country in 2008. Conclusions: It is feasible to design a measure with a composite outcome of death or serious morbidity after colon surgery that has a low burden for data collection, has substantial clinical importance, and has acceptable reliability.

Identification of modifiable factors for reducing readmission after colectomy: A national analysis

BACKGROUND Rates of hospital readmission are currently used for public reporting and pay for performance. Colectomy procedures account for a large number of readmissions among operative procedures. Our objective was to compare the importance of 3 groups of clinical variables (demographics, preoperative risk factors, and postoperative complications) in predicting readmission after colectomy procedures. METHODS Patient records (2005-2008) from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) were linked to Medicare inpatient claims. Patient demographics (n = 2), preoperative risk factors (n = 23), and 30-day postoperative complications (n = 17) were identified from ACS-NSQIP, whereas 30-day postoperative readmissions and costs were determined from Medicare. Multivariable logistic regression models were used to examine risk-adjusted predictors of colectomy readmission. RESULTS Among 12,981 colectomy patients, the 30-day postoperative readmission rate was 13.5%. Readmitted patients had slightly greater rates of comorbidities and indicators of clinical severity and substantially greater rates of complications than non-readmitted patients. After risk adjustment, patients with a complication were 3.3 times as likely to be readmitted as patients without a complication. Among individual complications, progressive renal failure and organ-space surgical site infection had the highest risk-adjusted relative risks of readmission (4.6 and 4.0, respectively). Demographic, preoperative risk factor, and postoperative complication variables increased the ability to discriminate readmissions (reflected by the c-statistic) by 5.3%, 23.3%, and 35.4%, respectively. CONCLUSION Postoperative complications after colectomy are more predictive of readmission than traditional risk factors. Focusing quality improvement efforts on preventing and managing postoperative complications may be the most important step toward reducing readmission rates.

Which Patients Require More Care after Hospital Discharge? An Analysis of Post-Acute Care Use among Elderly Patients Undergoing Elective Surgery

BACKGROUND The use of post-acute care is common among the elderly and accounts for

Morbidity and Mortality after Colorectal Procedures: Comparison of Data from the American College of Surgeons Case Log System and the ACS NSQIP

62 billion in annual Medicare expenditures. However, little is known about post-acute care use after surgery. STUDY DESIGN Data were merged between the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) and Medicare claims for 2005 to 2008. Post-acute care use, including skilled nursing facilities (SNF), inpatient rehabilitation facilities (IRF), and home health care (HHC) were analyzed for 3 operations: colectomy, pancreatectomy, and open abdominal aortic aneurysm repair. Controlling for both preoperative risk factors and the occurrence of postoperative complications, we used multinomial logistic regression to estimate the odds of use for each type of post-acute care after elective surgery compared with home discharge. RESULTS Post-acute care was used frequently for patients undergoing colectomy (40.0%; total n=10,932), pancreatectomy (46.0%; total n=2,144), and open abdominal aortic aneurysm (AAA) repair (44.9%; total n=1,736). Home health was the most frequently reported post-acute care service for each operation (range 23.2% to 31.5%) followed by SNF (range 12.0% to 15.0%), and then by IRF (range 2.5% to 5.4%). The majority of patients with at least 1 inpatient complication were discharged to post-acute care (range 58.6% for open AAA repair to 64.4% for colectomy). In multivariable analysis, specific preoperative risk factors, including advanced age, poor functional status, and inpatient complications were significantly associated with increased risk-adjusted odds of discharge to post-acute care for each operation studied. CONCLUSIONS Among elderly patients, post-acute care use is frequent after surgery and is significantly associated with several preoperative risk factors and postoperative inpatient complications. Further work is needed to ensure that post-acute care services are used appropriately and cost-effectively.

Extending the value of the National Surgical Quality Improvement Program claims dataset to study long-term outcomes: Rate of repeat ventral hernia repair

BACKGROUND Improving the quality of surgical care depends upon collection of robust data. The American College of Surgeons Case Log System enables surgeons to self-report patient risk factors and outcomes. In contrast, the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) uses trained data abstractors to record similar data and uses a strict data collection methodology. The objective of this study was to assess bias in data entry for colorectal cases by comparing data in these 2 registries. STUDY DESIGN One year of NSQIP (July 1, 2008 to June 30, 2009) and 7 years of Case Log (2003 to 2010) data were examined. Colorectal cases were identified by current procedural terminology code. The frequencies of comparably defined variables were compared, and mortality models were developed using logistic regression. Observed and expected mortality rates were compared. RESULTS Rates of most risk factor and outcome variables were significantly higher in NSQIP than those in Case Log. NSQIP had a higher unadjusted mortality rate (4.46% versus 3.69%, p < 0.001); however, the adjusted odds of mortality was significantly higher in Case Log (odds ratio 1.32, p < 0.05). The Case Log model overpredicted mortality in NSQIP by 22%, whereas the NSQIP model underpredicted mortality in Case Log by 12%. CONCLUSIONS Significant differences exist between risk factor and outcome data in NSQIP and Case Log for colorectal procedures. These differences demonstrate the need for standardized data collection methods, as is required by NSQIP, including use of standard definitions, adherence to a follow-up period for outcomes, and use of audits. These measures would improve the validity of using a self-reported database to evaluate and benchmark performance.

Are Procedures Codes in Claims Data a Reliable Indicator of Intraoperative Splenic Injury Compared with Clinical Registry Data

BACKGROUND Existing large clinical registries capture short-term follow-up. Yet, there are many important long-term outcomes in surgery, such as recurrence of a ventral hernia after ventral hernia repair. The goal of the current study was to conduct an exploratory analysis to determine whether the rates, timing, and risk factors for ventral hernia re-repair in claims data linked to registry data were consistent with the known clinical literature. STUDY DESIGN The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) and Medicare inpatient claims linked data set from 2005 to 2008 was queried to identify ventral hernia re-repairs after index ventral hernia repairs. Survival analysis was used to examine the ventral hernia re-repair rate over time and to quantify the relationship with clinical variables. RESULTS Of 3,730 index ventral hernia repairs identified in ACS-NSQIP, 247 patients (6.6%) underwent re-repair of a ventral hernia during the study period (2005-2008) in the Medicare claims data. ACS-NSQIP clinical variables that were associated with the ventral hernia re-repair rate in Medicare claims data 1 year after index ventral hernia repair were being a smoker (hazard ratio [HR] = 1.70, P = .02), body mass index (HR = 1.16, P = .04), and postoperative superficial surgical-site infection (HR = 2.88, P < .001). CONCLUSION Long-term rate and timing of ventral hernia re-repair obtained from claims data were an underestimate compared with clinical studies. Yet, several known clinical risk factors for recurrence in the clinical registry were associated with the re-repair rate in claims data at one year. It may be possible to study certain long-term outcomes using selected reoperation rates using the technique of linked clinical registry-claims data, with an understanding that event rates are conservative estimates.