Jeffrey A. Genaw

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.

Comparative Effectiveness of Unfractionated and Low-Molecular-Weight Heparin for Prevention of Venous Thromboembolism Following Bariatric Surgery

OBJECTIVE To evaluate the effectiveness and safety of 3 predominant venous thromboembolism (VTE) prophylaxis strategies among patients undergoing bariatric surgery. DESIGN Cohort study. SETTING The Michigan Bariatric Surgery Collaborative, a statewide clinical registry and quality improvement program. PATIENTS Twenty-four thousand seven hundred seventy-seven patients undergoing bariatric surgery between 2007 and 2012. INTERVENTIONS Unfractionated heparin preoperatively and postoperatively (UF/UF), UF heparin preoperatively and low-molecular-weight heparin postoperatively (UF/LMW), and LMW heparin preoperatively and postoperatively (LMW/LMW). MAIN OUTCOME MEASURES Rates of VTE, hemorrhage, and serious hemorrhage (requiring >4 U of blood products or reoperation) occurring within 30 days of surgery. RESULTS Overall, adjusted rates of VTE were significantly lower for the LMW/LMW (0.25%; P < .001) and UF/LMW (0.29%; P = .03) treatment groups compared with the UF/UF group (0.68%). While UF/LMW (0.22%; P = .006) and LMW/LMW (0.21%; P < .001) were similarly effective in patients at low risk of VTE (predicted risk <1%), LMW/LMW (1.46%; P = .10) seemed more effective than UF/LMW (2.36%; P = .90) for high-risk (predicted risk ≥1%) patients. There were no significant differences in rates of hemorrhage or serious hemorrhage among the treatment strategies. CONCLUSION Low-molecular-weight heparin is more effective than UF heparin for the prevention of postoperative VTE among patients undergoing bariatric surgery and does not increase rates of bleeding.

Risks and benefits of prophylactic inferior vena cava filters in patients undergoing bariatric surgery

BACKGROUND The United States Food and Drug Administration recently issued a warning about adverse events in patients receiving inferior vena cava (IVC) filters. OBJECTIVE To assess relationships between IVC filter insertion and complications while controlling for differences in baseline patient characteristics and medical venous thromboembolism prophylaxis. DESIGN Propensity-matched cohort study. SETTING The prospective, statewide, clinical registry of the Michigan Bariatric Surgery Collaborative. PATIENTS Bariatric surgery patients (n=35,477) from 32 hospitals during the years 2006 through 2012. INTERVENTION Prophylactic IVC filter insertion. MEASUREMENTS Outcomes included the occurrence of complications (pulmonary embolism, deep vein thrombosis, and overall combined rates of complications by severity) within 30 days of bariatric surgery. RESULTS There were no significant differences in baseline characteristics among the 1,077 patients with IVC filters and in 1,077 matched control patients. Patients receiving IVC filters had higher rates of pulmonary embolism (0.84% vs 0.46%; odds ratio [OR], 2.0; 95% confidence interval [CI], 0.6-6.5; P=0.232), deep vein thrombosis (1.2% vs 0.37%; OR, 3.3; 95% CI, 1.1-10.1; P=0.039), venous thromboembolism (1.9% vs 0.74%; OR, 2.7; 95% CI, 1.1-6.3, P=0.027), serious complications (5.8% vs 3.8%; OR, 1.6; 95% CI, 1.0-2.4; P=0.031), permanently disabling complications (1.2% vs 0.37%; OR, 4.3; 95% CI, 1.2-15.6; P=0.028), and death (0.7% vs 0.09%; OR, 7.0; 95% CI, 0.9-57.3; P=0.068). Of the 7 deaths among patients with IVC filters, 4 were attributable to pulmonary embolism and 2 to IVC thrombosis/occlusion. CONCLUSIONS We have identified no benefits and significant risks to the use of prophylactic IVC filters among bariatric surgery patients and believe that their use should be discouraged.

Variation in utilization of acid-reducing medication at 1 year following bariatric surgery: results from the Michigan Bariatric Surgery Collaborative ☆

BACKGROUND Morbidly obese patients undergoing bariatric surgery have high rates of gastroesophageal reflux and are often treated with acid-reducing medications (ARM) such as proton pump inhibitors or H2-blockers. The objective of this study was to evaluate the effect of bariatric procedures on the utilization of ARM. We analyzed data from the clinical registry of the Michigan Bariatric Surgery Collaborative on 35,477 patients undergoing bariatric surgery between January 2006 and October 2012 who completed both baseline and 1-year follow-up surveys. Procedures included laparoscopic adjustable gastric banding (LAGB, n=2,627), Roux-en-Y gastric bypass (RYGB, n=6,410), sleeve gastrectomy (SG, n=1,567), and biliopancreatic diversion with duodenal switch (BPD/DS, n=162). METHODS Rates of ARM at 1 year by procedure type were compared using logistic regression analysis. Models were adjusted for patient characteristics, baseline co-morbidities, weight loss, and hiatal hernia repair. RESULTS Overall ARM use at baseline was 37.7% and declined to 29.6% at 1 year after bariatric surgery. The proportion of patients starting an ARM at 1 year when they were not using one at baseline by procedure was LAGB (13.9%), RYGB (19.2%), SG (21.6%), and BPD/DS (26.7%). The proportion of patients discontinuing an ARM at 1 year when they were using one at baseline by procedure was LAGB (55.6%), RYGB (56.2%), SG (37.3%), and BPD/DS (42.1%). Compared with LAGB on multivariable analysis, the likelihood of ARM use at 1 year was higher for SG (OR 1.70, 95% CI 1.45-1.99) and BDP/DS (OR 1.53, CI .97-2.40) but not different for RYGB (OR 1.02, CI .90-1.16). CONCLUSION Overall ARM use decreases after bariatric surgery; however, it is not uniform and depends on procedure type. SG is a significant predictor for ARM use at 1 year.

Respiratory medication prescriptions before and after bariatric surgery

BACKGROUND Increased body mass index is associated with asthma and frequent respiratory complaints. Bariatric surgery often results in rapid weight loss associated with an improved respiratory status. OBJECTIVE To assess whether patients undergoing bariatric surgery would have fewer respiratory symptoms after surgery as evidenced by decreases in respiratory prescription drug claims. METHODS A retrospective cohort of 320 patients continuously enrolled in a large, southeast Michigan health maintenance organization were studied for 1 year before and 1 year after bariatric surgery. The health maintenance organization claims database was used to compare respiratory prescriptions filled before and after surgery. Respiratory medications included bronchodilator inhalers, inhaled corticosteroids, oral corticosteroids, theophylline, and leukotriene antagonists. RESULTS Of 320 surgical patients, 64 (20%) filled at least 1 respiratory medication prescription for a total of 468 prescriptions during the 2-year observation period. Of the prescriptions filled, 35% were beta-agonists, 38% inhaled corticosteroids, 12% oral corticosteroids, 15% leukotriene antagonists, and less than 1% theophylline. Total respiratory medication prescription fills decreased by 49% (from 314 to 154 prescriptions) in the postsurgical year, with only 43.1% of patients filling prescriptions in the year before surgery also filling a prescription in the postsurgical surveillance period. Analyses restricted to 40 patients with physician-diagnosed asthma revealed mean (SD) presurgical prescription fills of 7.0 (6.9) per year, decreasing to 3.8 (6.1) per year in the postsurgical year (P = .002). CONCLUSION Respiratory medication use decreases significantly after bariatric surgery. A secondary benefit of bariatric surgery may include a decrease in respiratory symptoms and concomitant medication use.

Self-reported remission of obstructive sleep apnea following bariatric surgery: cohort study

BACKGROUND Evidence on remission of obstructive sleep apnea (OSA) after bariatric surgery and its relation to weight loss is conflicting. We sought to identify factors associated with successful self-reported OSA remission in a large cohort of bariatric surgery patients. METHODS We analyzed data from the statewide, prospective clinical registry of the Michigan Bariatric Surgery Collaborative and identified 3,550 patients with OSA who underwent a primary bariatric procedure between June 2006 and October 2011 and had at least 1 year of follow-up data. We used multivariate logistic regression to identify preoperative factors associated with successful self-reported OSA remission, defined as discontinuation of continuous positive airway pressure or bilevel positive airway pressure at 1 year. Our regression model also included procedure type and weight loss at 1 year, divided into equal quintiles, as covariates. RESULTS The overall 1-year self-reported OSA remission rate was 60%. Significant predictors of remission included age category (per 10 yr) (OR .73, CI .69-.78), body mass index category (per 10 units) (OR .57, CI .54-.62), male gender (OR .58, CI .52-.69), hypertension (OR .83, CI .74-.99), depression (OR .78, CI .69-.88), pulmonary disease (OR .88, CI .78-.98), and baseline Health and Activities Limitations Index score (OR 1.70, CI 1.32-2.23). Relative to gastric banding, the adjusted odds of OSA remission were greater with gastric bypass (OR 2.38, CI 1.89-3.08), sleeve gastrectomy (OR 2.01, CI 1.44-2.55), and duodenal switch (OR 2.57, CI 1.02-7.26). The odds ratio of OSA remission increased stepwise through quintiles of 1-year weight loss. Relative to the lowest quintile, the odds ratios of remission in the 2(nd) through 5(th) quintiles were 1.44 (CI 1.11-1.84), 2.03 (CI 1.48-2.57), 2.47 (1.85-3.40), and 3.53 (CI 2.56-4.85). CONCLUSIONS Weight loss is an important predictor of self-reported OSA remission after bariatric surgery. However, independent of weight loss, there remain significant differences in the likelihood of remission between gastric banding and other bariatric procedures. This suggests that there may be metabolic, weight-independent effects of procedure type on self-reported OSA remission.

Pursuing bariatric surgery in an urban area: Gender and racial disparities and risk for psychiatric symptoms

BACKGROUND Bariatric surgery is effective for weight loss; however, only a small percentage of those who qualify choose to pursue it. Additionally, although psychiatric symptoms appear to be common among candidates, the risk factors for symptoms are not known. Therefore, the purpose of this study was to examine the characteristics of those who are pursuing bariatric surgery in an urban area, whether demographic disparities continue to exist, and identify characteristics of those who may be at higher risk for experiencing psychiatric symptoms. METHODS There were 424 bariatric candidates who completed a required psychological evaluation prior to bariatric surgery. RESULTS AND CONCLUSIONS Bariatric surgery candidates tended to be middle-aged, Caucasian females, which was unexpected when compared to the rates of obesity among these groups. Therefore, it appears that there are disparities in who chooses to seek out bariatric surgery compared to those who may qualify due to their obesity status. Cultural factors may play a role in why males and African Americans seek out bariatric surgery less frequently. Psychiatric symptoms among candidates are also common, with depression symptoms increasing with age and BMI. Perhaps the compounding effects of medical comorbidities over time are contributing to greater depressive symptoms in the older patients. Findings from this study suggest that we may need to explore ways of encouraging younger patients, males, and ethnic minorities to pursue bariatric surgery to increase weight loss success and decrease medical comorbidities.