Jonathan F. Finks

Trends in Hospital Volume and Operative Mortality for High-Risk Surgery

BACKGROUND There were numerous efforts in the United States during the previous decade to concentrate selected surgical procedures in high-volume hospitals. It remains unknown whether referral patterns for high-risk surgery have changed as a result and how operative mortality has been affected. METHODS We used national Medicare data to study patients undergoing one of eight different cancer and cardiovascular operations from 1999 through 2008. For each procedure, we examined trends in hospital volume and market concentration, defined as the proportion of Medicare patients undergoing surgery in the top decile of hospitals by volume per year. We used regression-based techniques to assess the effects of volume and market concentration on mortality over time, adjusting for case mix. RESULTS Median hospital volumes of four cancer resections (lung, esophagus, pancreas, and bladder) and of repair of abdominal aortic aneurysm (AAA) rose substantially. Depending on the procedure, higher hospital volumes were attributable to an increasing number of cases nationwide, an increasing market concentration, or both. Hospital volumes rose slightly for aortic-valve replacement but fell for coronary-artery bypass grafting and carotid endarterectomy. Operative mortality declined for all eight procedures, ranging from a relative decline of 8% for carotid endarterectomy (1.3% mortality in 1999 and 1.2% in 2008) to 36% for AAA repair (4.4% in 1999 and 2.8% in 2008). Higher hospital volumes explained a large portion of the decline in mortality for pancreatectomy (67% of the decline), cystectomy (37%), and esophagectomy (32%), but not for the other procedures. CONCLUSIONS Operative mortality with high-risk surgery fell substantially during the previous decade. Although increased market concentration and hospital volume have contributed to declining mortality with some high-risk cancer operations, declines in mortality with other procedures are largely attributable to other factors. (Funded by the National Institute on Aging.).

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.

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.

The comparative effectiveness of sleeve gastrectomy, gastric bypass, and adjustable gastric banding procedures for the treatment of morbid obesity.

Objective:To evaluate the comparative effectiveness of sleeve gastrectomy (SG), laparoscopic gastric bypass (RYGB), and laparoscopic adjustable gastric banding (LAGB) procedures. Background:Citing limitations of published studies, payers have been reluctant to provide routine coverage for SG for the treatment of morbid obesity. Methods:Using data from an externally audited, statewide clinical registry, we matched 2949 SG patients with equal numbers of RYGB and LAGB patients on 23 baseline characteristics. Outcomes assessed included complications occurring within 30 days, and weight loss, quality of life, and comorbidity remission at 1, 2, and 3 years after bariatric surgery. Results:Matching resulted in cohorts of SG, RYGB, and LAGB patients that were well balanced on baseline characteristics. Overall complication rates among patients undergoing SG (6.3%) were significantly lower than for RYGB (10.0%, P < 0.0001) but higher than for LAGB (2.4%, P < 0.0001). Serious complication rates were similar for SG (2.4%) and RYGB (2.5%, P = 0.736) but higher than for LAGB (1.0%, P < 0.0001). Excess body weight loss at 1 year was 13% lower for SG (60%) than for RYGB (69%, P < 0.0001), but was 77% higher for SG than for LAGB (34%, P < 0.0001). SG was similarly closer to RYGB than LAGB with regard to remission of obesity-related comorbidities. Conclusions:With better weight loss than LAGB and lower complication rates than RYGB, SG is a reasonable choice for the treatment of morbid obesity and should be covered by both public and private payers.

Predicting risk for serious complications with bariatric surgery: results from the Michigan Bariatric Surgery Collaborative.

Objectives:To develop a risk prediction model for serious complications after bariatric surgery. BackgroundDespite evidence for improved safety with bariatric surgery, serious complications remain a concern for patients, providers and payers. There is little population-level data on which risk factors can be used to identify patients at high risk for major morbidity. Methods:The Michigan Bariatric Surgery Collaborative is a statewide consortium of hospitals and surgeons, which maintains an externally-audited prospective clinical registry. We analyzed data from 25,469 patients undergoing bariatric surgery between June 2006 and December 2010. Significant risk factors on univariable analysis were entered into a multivariable logistic regression model to identify factors associated with serious complications (life threatening and/or associated with lasting disability) within 30 days of surgery. Bootstrap resampling was performed to obtain bias-corrected confidence intervals and c-statistic. Results:Overall, 644 patients (2.5%) experienced a serious complication. Significant risk factors (P < 0.05) included: prior VTE (odds ratio [OR] 1.90, confidence interval [CI] 1.41–2.54); mobility limitations (OR 1.61, CI 1.23–2.13); coronary artery disease (OR 1.53, CI 1.17–2.02); age over 50 (OR 1.38, CI 1.18–1.61); pulmonary disease (OR 1.37, CI 1.15–1.64); male gender (OR 1.26, CI 1.06–1.50); smoking history (OR 1.20, CI 1.02–1.40); and procedure type (reference lap band): duodenal switch (OR 9.68, CI 6.05–15.49); laparoscopic gastric bypass (OR 3.58, CI 2.79–4.64); open gastric bypass (OR 3.51, CI 2.38–5.22); sleeve gastrectomy (OR 2.46, CI 1.73–3.50). The c-statistic was 0.68 (bias-corrected to 0.66) and the model was well-calibrated across deciles of predicted risk. Conclusions:We have developed and validated a population-based risk scoring system for serious complications after bariatric surgery. We expect that this scoring system will improve the process of informed consent, facilitate the selection of procedures for high-risk patients, and allow for better risk stratification across studies of bariatric surgery.

The rise and fall of antireflux surgery in the United States

BackgroundNational rates of laparoscopic antireflux surgery grew steadily in the 1990s. Since then, a highly visible randomized trial has questioned the long-term effectiveness of antireflux surgery, several new endoscopic therapies have been developed, and proton pump inhibitors have become available over the counter. Whether these recent developments have had an impact on the use of antireflux surgery remains unknown.MethodsUsing data from the Nationwide Inpatient Sample, this study identified all patients older than 18 years who underwent antireflux surgery between 1994 and 2003. Sampling weights were used to estimate the total number of procedures performed in the United States each year. Population-based rates were determined using denominators from U.S. census data.ResultsConfirming the results of earlier studies, this study found that the annual number of antireflux procedures grew rapidly during the 1990s, peaking at 31,695 (15.7 cases per 100,000 adults) in 1999. After 1999, surgical rates declined steadily, falling approximately 30% by 2003 to 23,998 (11 cases per 100,000; p < 0.0001). Use of antireflux procedures fell more precipitously among younger patients (39% for 30- to 49-year-olds vs 12.5% for those older than 60 years; p < 0.0001) and at teaching hospitals (36% vs 23% at nonteaching hospitals; p < 0.0001). The proportion of cases managed laparoscopically remained stable after 1999.ConclusionsThe use of antireflux surgery in the United States has declined substantially. Although other factors may be involved, this trend may reflect new questions about the long-term effectiveness of surgery and suggests the need for prospective randomized clinical trials assessing current therapies.

Preoperative placement of inferior vena cava filters and outcomes after gastric bypass surgery

Objective:To assess relationships between inferior vena cava (IVC) filter placement and complications within 30 days of gastric bypass surgery. Summary of Background Data:IVC filters are increasingly being used as prophylaxis against postoperative pulmonary embolism in patients undergoing bariatric surgery, despite a lack of evidence of effectiveness. Methods:On the basis of data from a prospective clinical registry involving 20 Michigan hospitals, we identified 6376 patients undergoing gastric bypass surgery between 2006 and 2008. We then assessed relationships between IVC filter placement and complications within 30 days of surgery. We used propensity scores and fixed effects logistic regression to control for potential selection bias. Results:A total of 542 gastric bypass patients (8.5%) underwent preoperative IVC filter placement, most of whom (65%) had no history of venous thromboembolism. The use of IVC filters for gastric bypass patients varied widely across hospitals (range, 0%–34%). IVC filter patients did not have reduced rates of postoperative venous thromboembolism (adjusted odds ratio [OR], = 1.28; 95% confidence interval [CI], 0.51–3.21), serious complications (adjusted OR, = 1.40; 95% CI, 0.91–2.16), or death/permanent disability (adjusted OR, = 2.49; 95% CI, 0.99–6.26). More than half (57%) of the IVC filter patients in the latter group had a fatal pulmonary embolism or complications directly related to the IVC filter itself, including filter migration or thrombosis of the vena cava. In subgroup analyses, we were unable to identify any patient group for whom IVC filters were associated with improved outcomes. Conclusions:Prophylactic IVC filters for gastric bypass surgery do not reduce the risk of pulmonary embolism and may lead to additional complications.

Predicting risk for venous thromboembolism with bariatric surgery: results from the Michigan Bariatric Surgery Collaborative.

Objective:We sought to identify risk factors for venous thromboembolism (VTE) among patients undergoing bariatric surgery in Michigan. Background:VTE remains a major source of morbidity and mortality after bariatric surgery. It is unclear which factors should be used to identify patients at high risk for VTE. Methods:The Michigan Bariatric Surgery Collaborative maintains a prospective clinical registry of bariatric surgery patients. For this study, we identified all patients undergoing primary bariatric surgery between June 2006 and April 2011 and determined rates of VTE. Potential risk factors for VTE were analyzed using a hierarchical logistic regression model, accounting for clustering of patients within hospitals. Significant risk factors were used to develop a risk calculator for development of VTE after bariatric surgery. Results:Among 27,818 patients who underwent bariatric surgery during the study period, 93 patients (0.33%) experienced a VTE complication, including 51 patents with pulmonary embolism. There were 8 associated deaths. Significant risk factors included previous history of VTE (OR 4.15, CI 2.42–7.08); male gender (OR 2.08, CI 1.36–3.19); operative time more than 3 hours (OR 1.86, CI 1.07–3.24); BMI category (per 10 units) (OR 1.37, CI 1.06–1.75); age category (per 10 years) (OR 1.25, CI 1.03–1.51); and procedure type (reference adjustable gastric band): duodenal switch (OR 9.45, CI 2.50–35.97); open gastric bypass (OR 6.48, CI 2.17–19.41); laparoscopic gastric bypass (OR 3.97, CI 1.77–8.91); and sleeve gastrectomy (OR 3.50, CI 1.30–9.34). Nearly 97% of patients had a predicted VTE risk less than 1%. Conclusions:In this population-based study, overall VTE rates were low among patients undergoing bariatric surgery. The use of an empirically based risk calculator will allow for the development of a risk-stratified approach to VTE prophylaxis.

Changes in Bariatric Surgery Procedure Use in Michigan, 2006-2013

Bariatric surgery is the most effective therapy available for significant and sustainable weight loss in morbidly obese patients.1,2 As a result of the rising prevalence of obesity, improvements in perioperative safety, and expanded insurance coverage, bariatric surgery utilization has increased in the last decade.3,4 Changes in procedure use over time reflect emerging evidence regarding the comparative safety and effectiveness of available procedures.1,2,5 An understanding of current trends in bariatric procedure utilization is essential to primary care physicians counseling morbidly obese patients considering surgical intervention. Though recent reports have documented increased use of sleeve gastrectomy (SG) in certain populations,4,6 the extent to which this procedure has supplanted other procedures, such as Roux-en-Y gastric bypass (RYGB) or laparoscopic adjustable gastric banding (LAGB), is poorly understood. Moreover, it is unclear if relative utilization differs within clinical subgroups that might be predicted to have better outcomes with a specific procedure. To better understand current trends in bariatric surgery utilization, we examined procedure rates in patients undergoing bariatric surgery in Michigan between 2006 and 2013.

Effects of Resident Involvement on Complication Rates after Laparoscopic Gastric Bypass

BACKGROUND Although resident involvement has been shown to be safe for most procedures, the impact of residents on outcomes after complex laparoscopic procedures is not well understood. We sought to examine the impact of resident involvement on outcomes after bariatric surgery using a population-based clinical registry. STUDY DESIGN We analyzed 17,057 patients who underwent a primary laparoscopic gastric bypass in the 35-hospital Michigan Bariatric Surgery Collaborative from July 2006 to August 2012. Resident involvement was characterized at the surgeon level. Using hierarchical logistic regression, we examined the influence of resident involvement on 30-day complications, accounting for patient characteristics as well as hospital and surgeon case volume. To evaluate potential mediating factors for specific complications, we also adjusted for operative duration. RESULTS Risk-adjusted 30-day complication rates with and without residents were 13.0% and 8.5%, respectively (p < 0.01). Resident involvement was independently associated with wound infection (odds ratio [OR] = 2.06; 95% CI, 1.24-3.43) and venous thromboembolism (OR = 2.01; 95% CI, 1.19-3.40), but not with any other medical or surgical complications. Operative duration was longer with resident involvement (median duration with residents 129 minutes vs 88 minutes without; p < 0.01). After adjusting for operative duration, resident involvement was still independently associated with wound infection (OR = 1.67; 95% CI, 1.01-2.76), but not venous thromboembolism (OR = 1.73; 95% CI, 0.99-3.04). CONCLUSIONS Resident involvement in laparoscopic gastric bypass is independently associated with wound infections and venous thromboembolism. The effect appears to be mediated in part by longer operative times. These findings highlight the importance of strategies to assess and improve resident technical proficiency outside the operating room.