Justin B. Dimick

Variation in hospital mortality associated with inpatient surgery.

BACKGROUND Hospital mortality that is associated with inpatient surgery varies widely. Reducing rates of postoperative complications, the current focus of payers and regulators, may be one approach to reducing mortality. However, effective management of complications once they have occurred may be equally important. METHODS We studied 84,730 patients who had undergone inpatient general and vascular surgery from 2005 through 2007, using data from the American College of Surgeons National Surgical Quality Improvement Program. We first ranked hospitals according to their risk-adjusted overall rate of death and divided them into five groups. For hospitals in each overall mortality quintile, we then assessed the incidence of overall and major complications and the rate of death among patients with major complications. RESULTS Rates of death varied widely across hospital quintiles, from 3.5% in very-low-mortality hospitals to 6.9% in very-high-mortality hospitals. Hospitals with either very high mortality or very low mortality had similar rates of overall complications (24.6% and 26.9%, respectively) and of major complications (18.2% and 16.2%, respectively). Rates of individual complications did not vary significantly across hospital mortality quintiles. In contrast, mortality in patients with major complications was almost twice as high in hospitals with very high overall mortality as in those with very low overall mortality (21.4% vs. 12.5%, P<0.001). Differences in rates of death among patients with major complications were also the primary determinant of variation in overall mortality with individual operations. CONCLUSIONS In addition to efforts aimed at avoiding complications in the first place, reducing mortality associated with inpatient surgery will require greater attention to the timely recognition and management of complications once they occur.

Surgical Skill and Complication Rates after Bariatric Surgery

BACKGROUND Clinical outcomes after many complex surgical procedures vary widely across hospitals and surgeons. Although it has been assumed that the proficiency of the operating surgeon is an important factor underlying such variation, empirical data are lacking on the relationships between technical skill and postoperative outcomes. METHODS We conducted a study involving 20 bariatric surgeons in Michigan who participated in a statewide collaborative improvement program. Each surgeon submitted a single representative videotape of himself or herself performing a laparoscopic gastric bypass. Each videotape was rated in various domains of technical skill on a scale of 1 to 5 (with higher scores indicating more advanced skill) by at least 10 peer surgeons who were unaware of the identity of the operating surgeon. We then assessed relationships between these skill ratings and risk-adjusted complication rates, using data from a prospective, externally audited, clinical-outcomes registry involving 10,343 patients. RESULTS Mean summary ratings of technical skill ranged from 2.6 to 4.8 across the 20 surgeons. The bottom quartile of surgical skill, as compared with the top quartile, was associated with higher complication rates (14.5% vs. 5.2%, P<0.001) and higher mortality (0.26% vs. 0.05%, P=0.01). The lowest quartile of skill was also associated with longer operations (137 minutes vs. 98 minutes, P<0.001) and higher rates of reoperation (3.4% vs. 1.6%, P=0.01) and readmission (6.3% vs. 2.7%) (P<0.001). CONCLUSIONS The technical skill of practicing bariatric surgeons varied widely, and greater skill was associated with fewer postoperative complications and lower rates of reoperation, readmission, and visits to the emergency department. Although these findings are preliminary, they suggest that peer rating of operative skill may be an effective strategy for assessing a surgeons proficiency.

Complications, failure to rescue, and mortality with major inpatient surgery in medicare patients.

Objective:We sought to determine whether hospital variations in surgical mortality were due to differences in complication rates or failure to rescue rates (ie, case-fatality rates in patients with a complication). Background:Wide variations in mortality after major surgery are becoming increasingly apparent. The clinical mechanisms underling these variations are largely unexplored. Methods:We studied all Medicare beneficiaries undergoing 6 major operations in 2005 to 2006: pancreatectomy, esophagectomy, abdominal aortic aneurysm repair, coronary artery bypass grafting, aortic valve replacement, and mitral valve replacement. We ranked hospitals according to risk-adjusted mortality and divided them into 5 equal groups. We then compared the incidence of complications and rates of failure to rescue between the top 20% of hospitals (“best”) and bottom 20% of hospitals (“worst”). Analyses were conducted for all operations combined and for each individual procedure. Results:For all 6 operations combined, the worst hospitals had mortality rates 2.5-fold higher than the best hospitals (8.0% vs. 3.0%). However, complication rates were similar at worst and best hospitals (36.4% vs. 32.7%). In contrast, failure to rescue rates were much higher at the worst compared with the best hospitals (16.7% vs. 6.8%). These findings persisted in analyses with individual operations and specific complications. Conclusions:Reducing variations in mortality will require strategies to improve the ability of high-mortality hospitals to manage postoperative complications.

Surgical treatment of intact thoracoabdominal aortic aneurysms in the United States: Hospital and surgeon volume-related outcomes

OBJECTIVE Surgical treatment of intact thoracoabdominal aortic aneurysm (TAAA) is crucial to prevent rupture but is associated with high perioperative mortality. We tested the hypothesis that provider volume of surgical treatment of TAAA is an important determinant of operative outcome. Patients and methods Clinical information regarding repair of intact TAAA in 1542 patients from 1988 to 1998 was obtained from the Nationwide Inpatient Sample (NIS), a stratified discharge database of a representative 20% of US hospitals. Demographic data included age, sex, race, nature of admission, and comorbid conditions. Annual hospital volume of TAAA treated was grouped into terciles and defined as low (LVH; 1-3 cases [median, 1]), medium (MVH; 2-9 cases [median, 4]), or high (HVH; 5-31 cases [median, 12]). Annual surgeon volume was defined as low (LVS; 1-2 cases [median, 1]) or high (HVS; 3-18 cases [median, 7]). The primary outcome measure was in-hospital postoperative mortality. Secondary outcome measures included length of stay, and cardiac, pulmonary, and renal complications. Adjusted and unadjusted analyses were conducted. RESULTS Overall mortality was 22.3%. Mortality improved over time. LVH and HVH differed in mortality rates (27.4% vs 15.0%; P <.001). Mortality between LVS and HVS also differed significantly (25.6% vs 11.0%; P <.001). When controlling for patient demographic data, comorbid conditions, and postoperative complications, both hospital and surgeon volume were significant predictors of mortality for intact TAAA repair (LVS: odds ratio [OR] 2.6, P <.001; LVH: OR 2.2, P <.001; and MVH: OR 1.7, P =.004). CONCLUSIONS Greater hospital and surgeon TAAA treatment volumes contribute to better outcome. Given the relative high perioperative mortality associated with TAAA repair, regionalization of care to high-volume providers with consistently lower postoperative mortality deserves consideration by patients, physicians, and health care planners.

Hospital Complication Rates With Bariatric Surgery in Michigan

CONTEXT Despite the growing popularity of bariatric surgery, there remain concerns about perioperative safety and variation in outcomes across hospitals. OBJECTIVE To assess complication rates of different bariatric procedures and variability in rates of serious complications across hospitals and according to procedure volume and center of excellence (COE) status. DESIGN, SETTING, AND PATIENTS Involving 25 hospitals and 62 surgeons statewide, the Michigan Bariatric Surgery Collaborative (MBSC) administers an externally audited, prospective clinical registry. We evaluated short-term morbidity in 15,275 Michigan patients undergoing 1 of 3 common bariatric procedures between 2006 and 2009. We used multilevel regression models to assess variation in risk-adjusted complication rates across hospitals and the effects of procedure volume and COE designation (by the American College of Surgeons or American Society for Metabolic and Bariatric Surgery) status. MAIN OUTCOME MEASURE Complications occurring within 30 days of surgery. RESULTS Overall, 7.3% of patients experienced perioperative complications, most of which were wound problems and other minor complications. Serious complications were most common after gastric bypass (3.6%; 95% confidence interval [CI], 3.2%-4.0%), followed by sleeve gastrectomy (2.2%; 95% CI, 1.2%-3.2%), and laparoscopic adjustable gastric band (0.9%; 95% CI, 0.6%-1.1%) procedures (P < .001). Mortality occurred in 0.04% (95% CI, 0.001%-0.13%) of laparoscopic adjustable gastric band, 0 sleeve gastrectomy, and 0.14% (95% CI, 0.08%-0.25%) of the gastric bypass patients. After adjustment for patient characteristics and procedure mix, rates of serious complications varied from 1.6% (95% CI, 1.3-2.0) to 3.5% (95% CI, 2.4-5.0) (risk difference, 1.9; 95% CI, 0.08-3.7) across hospitals. Average annual procedure volume was inversely associated with rates of serious complications at both the hospital level (< 150 cases, 4.1%; 95% CI, 3.0%-5.1%; 150-299 cases, 2.7%; 95% CI, 2.2-3.2; and > or = 300 cases, 2.3%; 95% CI, 2.0%-2.6%; P = .003) and surgeon level (< 100 cases, 3.8%; 95% CI, 3.2%-4.5%; 100-249 cases, 2.4%; 95% CI, 2.1%-2.8%; > or = 250 cases, 1.9%; 95% CI, 1.4%-2.3%; P = .001). Adjusted rates of serious complications were similar in COE and non-COE hospitals (COE, 2.7%; 95% CI, 2.5%-3.1%; non-COE, 2.0%; 95% CI, 1.5%-2.4%; P = .41). CONCLUSIONS The frequency of serious complications among patients undergoing bariatric surgery in Michigan was relatively low. Rates of serious complications are inversely associated with hospital and surgeon procedure volume, but unrelated to COE accreditation by professional organizations.

Hospital volume and failure to rescue with high-risk surgery.

Introduction:Although the relationship between surgical volume and mortality is well established, the mechanisms underlying these associations remain uncertain. We sought to determine whether increased mortality at low-volume centers was due to higher complication rates or less success in rescuing patients from complications. Methods:Using 2005 to 2007 Medicare data, we identified patients undergoing 3 high-risk cancer operations: gastrectomy, pancreatectomy, and esophagectomy. We first ranked hospitals according to their procedural volume for these operations and divided them into 5 equal groups (quintiles) based on procedure volume cutoffs that most closely resulted in an equal distribution of patients through the quintiles. We then compared the incidence of major complications and “failure to rescue” (ie, case fatality among patients with complications) across hospital quintiles. We performed this analysis for all operations combined and for each operation individually. Results:With all 3 operations combined, failure to rescue had a much stronger relationship to hospital volume than postoperative complications. Very low-volume (lowest quintile) hospitals had only slightly higher complications rates (42.7% vs. 38.9%; odds ratio 1.17, 95% confidence interval, 1.02–1.33), but markedly higher failure-to-rescue rates (30.3% vs. 13.1%; odds ratio 2.89, 95% confidence interval, 2.40–3.48) compared with very high-volume hospitals (highest quintile). These relationships also held true for individual operations. For example, patients undergoing pancreatectomy at very low-volume hospitals were 1.7 times more likely to have a major complication than those at very high-volume hospitals (38.3% vs. 27.7%, P<0.05), but 3.2 times more likely to die once those complications had occurred (26.0% vs. 9.9%, P<0.05). Conclusions:Differences in mortality between high and low-volume hospitals are not associated with large differences in complication rates. Instead, these differences seem to be associated with the ability of a hospital to effectively rescue patients from complications. Strategies focusing on the timely recognition and management of complications once they occur may be essential to improving outcomes at low-volume hospitals.

Blueprint for a New American College of Surgeons: National Surgical Quality Improvement Program

i A t c w m c “ m p m he need for hospitals and surgeons to systematically track he quality of surgical care they provide has never been tronger. Effective measurement is, of course, essential for argeting and evaluating the effects of local quality imrovement activities. They also face new external pressures. he American Board of Surgery has implemented new tandards for Maintenance of Certification (MOC) that equire surgeons to monitor their own performance. Reglators, including the Joint Commission, are demanding vidence that hospitals are assessing key indicators of surical safety and monitoring surgeon-specific performance s part of the credentialing process. Payers in both public nd private sectors are rapidly implementing centers of xcellence and pay-for-performance programs, holding ospitals and surgeons accountable to a growing number of rocessand outcomes-oriented quality indicators. The American College of Surgeons-National Surgical uality Improvement Program (ACS-NSQIP), the most idely recognized quality measurement system for noncardiac urgery in the United States, aims to meet these needs. Orignally developed within the Department of Veterans Affairs ealth system, NSQIP was launched in the private sector in 999 in a pilot study involving a small number of academic enters. In 2004, the program partnered with the American ollege of Surgeons, aiming to disseminate ACS-NSQIP naionwide. At this writing, more than 200 hospitals are submiting data to the program, with many more in the process of nrollment. Although general and vascular surgery remain the

Methods for Evaluating Changes in Health Care Policy: The Difference-in-Differences Approach

Observational studies are commonly used to evaluate the changes in outcomes associated with health care policy implementation. An important limitation in using observational studies in this context is the need to control for background changes in outcomes that occur with time (eg, secular trends affecting outcomes). The difference-in-differences approach is increasingly applied to address this problem.1 In this issue of JAMA, studies by Rajaram and colleagues2 and Patel and colleagues3 used the difference-in-differences approach to evaluate the changes that occurred following the 2011 Accreditation Council for Graduate Medical Education (ACGME) duty hour reforms. The 2 studies were conducted with different data sources and study populations but used similar methods.

Hospital volume and operative mortality in the modern era.

Objective:To determine whether the relationship between hospital volume and mortality has changed over time. Background:It is generally accepted that hospital volume is associated with mortality in high-risk procedures. However, as surgical safety has improved over the last decade, recent evidence has suggested that the inverse relationship has diminished or been eliminated. Methods:Using national Medicare claims data from 2000 through 2009, we examined mortality among 3,282,127 patients who underwent 1 of 8 gastrointestinal, cardiac, or vascular procedures. Hospitals were stratified into quintiles of operative volume. Using multivariable logistic regression models to adjust for patient characteristics, we examined the relationship between hospital volume and mortality, and assessed for changes over time. We performed sensitivity analyses using hierarchical logistic regression modeling with hospital-level random effects to confirm our results. Results:Throughout the 10-year period, a significant inverse relationship was observed in all procedures. In 5 of the 8 procedures studied, the strength of the volume-outcome relationship increased over time. In esophagectomy, for example, the adjusted odds ratio of mortality in very low volume hospitals compared to very high volume hospitals increased from 2.25 [95% confidence interval (CI): 1.57–3.23] in 2000–2001 to 3.68 (95% CI: 2.66–5.11) in 2008–2009. Only pancreatectomy showed a notable decrease in strength of the relationship over time, from 5.83 (95% CI: 3.64–9.36) in 2000–2001, to 3.08 (95% CI: 2.07–4.57) in 2008–2009. Conclusions:For all procedures examined, higher volume hospitals had significantly lower mortality rates than lower volume hospitals. Despite recent improvements in surgical safety, the strong inverse relationship between hospital volume and mortality persists in the modern era.

Surgeon volume as an indicator of outcomes after carotid endarterectomy: An effect independent of specialty practice and hospital volume

BACKGROUND High-volume hospitals have been shown to have superior outcomes after carotid endarterectomy (CEA), but the contribution of surgeon volume and specialty practice to CEA outcomes in a national sample is unknown. STUDY DESIGN Using the National Inpatient Sample for 1996 and 1997, 35,821 patients who underwent CEA (ICD-9-CM code 3812) and had data for unique surgeon identification were studied. Surgeons were categorized in terms of annual CEA volume as low-volume surgeons (< 10 procedures), medium-volume surgeons (10 to 29), and high-volume surgeons (> or = 30). Data from cardiac, general, neurologic, and vascular surgical practices were analyzed. In-hospital mortality, postoperative stroke, and prolonged length of stay (> 4 days) were the primary outcomes variables. Unadjusted and case-mix adjusted analyses were performed. RESULTS The overall in-hospital mortality was 0.61%. CEA was performed annually by high-volume surgeons in 52% of patients, by medium-volume surgeons in 30% of patients, and by low-volume surgeons in 18% of patients. Observed mortality by surgeon volume was 0.44% for high-volume surgeons, 0.63% for medium-volume surgeons, and 1.1% for low-volume surgeons (p < 0.001). The postoperative stroke rate was 1.14% for high-volume surgeons, 1.63% for medium-volume surgeons, and 2.03% for low-volume surgeons (p < 0.001). Surgeon specialty had no statistically significant effect on mortality or postoperative stroke. In the logistic regression model, increased risk of mortality was associated with emergent admission (odds ratio [OR] = 2.1; 95% confidence interval [CI] 1.6 to 2.8, p < 0.001), patient age > 65 years (OR = 2.0; 95% CI 1.3 to 3.1, p = 0.001), low-volume surgeon (OR = 1.9; 95% CI 1.4 to 2.5, p < 0.001), and COPD (OR = 1.8; 95% CI 1.3 to 2.5, p = 0.001). Low hospital CEA volume (< 100) was not a significant risk factor in the multivariate analysis. CONCLUSIONS More than 50% of the CEAs in the United States are performed by high-volume surgeons with superior outcomes. Health policy efforts should focus on reducing the number of low-volume surgeons, regardless of surgeon specialty or total hospital CEA volume.