Reduction in Long-term Mortality After Sleeve Gastrectomy and Gastric Bypass Compared to Nonsurgical Patients With Severe Obesity.

OBJECTIVE: To separately compare the long-term risk of mortality among bariatric surgical patients undergoing either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) to large, matched, population-based cohorts of patients with severe obesity who did not undergo surgery. BACKGROUND: Bariatric surgery has been associated with reduced long-term mortality compared to usual care for severe obesity which is particularly relevant in the COVID-19 era. Most prior studies involved the RYGB operation and there is less long-term data on the SG. METHODS: In this retrospective, matched cohort study, patients with a body mass index ≥35 kg/m 2 who underwent bariatric surgery from January 2005 to September 2015 in three integrated health systems in the United States were matched to nonsurgical patients on site, age, sex, body mass index, diabetes status, insulin use, race/ethnicity, combined Charlson/Elixhauser comorbidity score, and prior health care utilization, with follow-up through September 2015. Each procedure (RYGB, SG) was compared to its own control group and the two surgical procedures were not directly compared to each other. Multivariable-adjusted Cox regression analysis investigated time to all-cause mortality (primary outcome) comparing each of the bariatric procedures to usual care. Secondary outcomes separately examined the incidence of cardiovascular-related death, cancer related-death, and diabetes related-death. RESULTS: Among 13,900 SG, 17,258 RYGB, and 87,965 nonsurgical patients, the 5-year follow-up rate was 70.9%, 72.0%, and 64.5%, respectively. RYGB and SG were each associated with a significantly lower risk of all-cause mortality compared to nonsurgical patients at 5-years of follow-up (RYGB: HR = 0.43; 95% CI: 0.35,0.54; SG: HR = 0.28; 95% CI: 0.13,0.57) Similarly, RYGB was associated with a significantly lower 5-year risk of cardiovascular-(HR = 0.27; 95% CI: 0.20, 0.37), cancer- (HR = 0.54; 95% CI: 0.39, 0.76), and diabetes-related mortality (HR = 0.23; 95% CI:0.15, 0.36). There was not enough follow-up time to assess 5-year cause-specific mortality in SG patients, but at 3-years follow-up, there was significantly lower risk of cardiovascular- (HR = 0.33; 95% CI:0.19, 0.58), cancer- (HR = 0.26; 95% CI:0.11, 0.59), and diabetes-related (HR = 0.15; 95% CI:0.04, 0.53) mortality for SG patients. CONCLUSION: This study confirms and extends prior findings of an association with better survival following bariatric surgery in RYGB patients compared to controls and separately demonstrates that the SG operation also appears to be associated with lower mortality compared to matched control patients with severe obesity that received usual care. These results help to inform the tradeoffs between long-term benefits and risks of bariatric surgery.

Bariatric Surgery is Associated With Reduced Risk of Breast Cancer in Both Premenopausal and Postmenopausal Women.

OBJECTIVE: This retrospective cohort study examined whether bariatric surgery is associated with reduced risk of breast cancer among pre- and postmenopausal women. BACKGROUND: Obesity is associated with increased risk of breast cancer, but the impact of weight loss on breast cancer risk has been difficult to quantify. METHODS: The cohort included obese (body mass index ≥35 kg/m) patients enrolled in an integrated health care delivery system between 2005 and 2012 (with follow-up through 2014). Female bariatric surgery patients (N = 17,998) were matched on body mass index, age, study site, and comorbidity index to 53,889 women with no bariatric surgery. Kaplan-Meier curves and Cox proportional hazards models were used to examine incident breast cancer up to 10 years after bariatric surgery. Pre- and postmenopausal women were examined separately, and further classified by estrogen receptor (ER) status. RESULTS: The analysis included 301 premenopausal and 399 postmenopausal breast cancer cases. In multivariable adjusted models, bariatric surgery was associated with a reduced risk of both premenopausal (HR = 0.72, 95% CI, 0.54-0.94) and postmenopausal (HR = 0.55, 95% CI, 0.42-0.72) breast cancer. Among premenopausal women, the effect of bariatric surgery was more pronounced among ER-negative cases (HR = 0.36, 95% CI, 0.16-0.79). Among postmenopausal women, the effect was more pronounced in ER-positive cases (HR = 0.52, 95% CI, 0.39-0.70). CONCLUSIONS: Bariatric surgery was associated with a reduced risk of breast cancer among severely obese women. These findings have significant public health relevance because the prevalence of obesity continues to rise, and few modifiable breast cancer risk factors have been identified, especially for premenopausal women.

Bariatric Surgery and the Risk of Cancer in a Large Multisite Cohort.

OBJECTIVE: To determine whether bariatric surgery is associated with a lower risk of cancer. BACKGROUND: Obesity is strongly associated with many types of cancer. Few studies have examined the relationship between bariatric surgery and cancer risk. METHODS: We conducted a retrospective cohort study of patients undergoing bariatric surgery between 2005 and 2012 with follow-up through 2014 using data from a large integrated health insurance and care delivery systems with 5 study sites. The study included 22,198 subjects who had bariatric surgery and 66,427 nonsurgical subjects matched on sex, age, study site, body mass index, and Elixhauser comorbidity index. Multivariable Cox proportional-hazards models were used to examine incident cancer up to 10 years after bariatric surgery compared to the matched nonsurgical patients. RESULTS: After a mean follow-up of 3.5 years, we identified 2543 incident cancers. Patients undergoing bariatric surgery had a 33% lower hazard of developing any cancer during follow-up [hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.60, 0.74, P < 0.001) compared with matched patients with severe obesity who did not undergo bariatric surgery, and results were even stronger when the outcome was restricted to obesity-associated cancers (HR 0.59, 95% CI 0.51, 0.69, P < 0.001). Among the obesity-associated cancers, the risk of postmenopausal breast cancer (HR 0.58, 95% CI 0.44, 0.77, P < 0.001), colon cancer (HR 0.59, 95% CI 0.36, 0.97, P = 0.04), endometrial cancer (HR 0.50, 95% CI 0.37, 0.67, P < 0.001), and pancreatic cancer (HR 0.46, 95% CI 0.22, 0.97, P = 0.04) was each statistically significantly lower among those who had undergone bariatric surgery compared with matched nonsurgical patients. CONCLUSIONS: In this large, multisite cohort of patients with severe obesity, bariatric surgery was associated with a lower risk of incident cancer, particularly obesity-associated cancers, such as postmenopausal breast cancer, endometrial cancer, and colon cancer. More research is needed to clarify the specific mechanisms through which bariatric surgery lowers cancer risk.

Bariatric Surgery and the Long-Term Risk of Venous Thromboembolism: A Population-Based Cohort Study.

PURPOSE: Bariatric surgery is associated with a greater venous thromboembolism (VTE) risk in the weeks following surgery, but the long-term risk of VTE is incompletely characterized. We evaluated bariatric surgery in relation to long-term VTE risk. MATERIALS AND METHODS: This population-based retrospective matched cohort study within three United States-based integrated health care systems included adults with body mass index (BMI) ≥ 35 kg/m2 who underwent bariatric surgery between January 2005 and September 2015 (n = 30,171), matched to nonsurgical patients on site, age, sex, BMI, diabetes, insulin use, race/ethnicity, comorbidity score, and health care utilization (n = 218,961). Follow-up for incident VTE ended September 2015 (median 9.3, max 10.7 years). RESULTS: Our population included 30,171 bariatric surgery patients and 218,961 controls; we identified 4068 VTE events. At 30 days post-index date, bariatric surgery was associated with a fivefold greater VTE risk (HRadj = 5.01; 95% CI = 4.14, 6.05) and a nearly fourfold greater PE risk (HRadj = 3.93; 95% CI = 2.87, 5.38) than no bariatric surgery. At 1 year post-index date, bariatric surgery was associated with a 48% lower VTE risk and a 70% lower PE risk (HRadj = 0.52; 95% CI = 0.41, 0.66 and HRadj = 0.30; 95% CI = 0.21, 0.44, respectively). At 5 years post-index date, lower VTE risks persisted, with bariatric surgery associated with a 41% lower VTE risk and a 55% lower PE risk (HRadj = 0.59; 95% CI = 0.48, 0.73 and HRadj = 0.45; 95% CI = 0.32, 0.64, respectively). CONCLUSION: Although in the short-term bariatric surgery is associated with a greater VTE risk, in the long-term, it is associated with a substantially lower risk.

Predictors of Complications Following Bariatric Surgery for Adolescent Patients.

BACKGROUND: Bariatric surgery for adolescent patients has been shown to be safe but potentially underutilized. A better understanding of operative risk in adolescents may temper apprehension to its adoption. This study intends to examine the association between preoperative risk factors and complications following bariatric surgery for adolescent patients. METHODS: The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program databank (2015-2020) was queried for all adolescent patients (10 to 19 years). Only patients who underwent sleeve gastrectomy or gastric bypass were included. Multivariable regression examined the association between patient characteristics and complications. RESULTS: A total of 7785 adolescent patients satisfied inclusion criteria. The median age was 18 years, 1737 (22%) were male, and the median body mass index was 46. Of all patients, 6675 (86%) and 1310 (14%) underwent sleeve gastrectomy and gastric bypass, respectively. Preoperative chronic steroid use was significantly associated with higher rates of leak (odds ratio [OR] 7.327, P = .009), bleeding (OR 10.791, P = .003), and reoperation (OR 7.685, P < .001). While Pacific Islander race was also significantly associated with higher rates of reoperation (OR 11.773, P = .039), Asian race was significantly associated with higher rates of bleeding (OR 14.527, P = .042). A history of gastroesophageal reflux disease was associated with higher rates of postoperative reintervention (OR 2.306, P = .004). DISCUSSION: Readily identifiable preoperative patient characteristics are significantly associated with higher rates of postoperative complications following adolescent bariatric surgery. Additional research is required to determine whether tailoring treatment based on these characteristics can improve outcomes.

Making lemonade with lemons: a multicenter effort to improve outpatient sleeve gastrectomy amid the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic impacted healthcare delivery worldwide. Resource limitations prompted a multicenter quality initiative to enhance outpatient sleeve gastrectomy workflow and reduce the inpatient hospital burden. OBJECTIVES: This study aimed to determine the efficacy of this initiative, as well as the safety of outpatient sleeve gastrectomy and potential risk factors for inpatient admission. SETTING: A retrospective analysis of sleeve gastrectomy patients was conducted from February 2020 to August 2021. METHODS: Inclusion criteria were adult patients discharged on postoperative day 0, 1, or 2. Exclusion criteria were body mass index ≥60 kg/m2 and age ≥65 years. Patients were divided into outpatient and inpatient cohorts. Demographic, operative, and postoperative variables were compared, as well as monthly trends in outpatient versus inpatient admission. Potential risk factors for inpatient admission were assessed, as well as early Clavien-Dindo complications. RESULTS: Analysis included 638 sleeve gastrectomy surgeries (427 outpatient, 211 inpatient). Significant differences between cohorts were age, co-morbidities, surgery date, facility, operative duration, and 30-day emergency department (ED) readmission. Monthly frequency of outpatient sleeve gastrectomy rose as high as 71% regionally. An increased number of 30-day ED readmissions was found for the inpatient cohort (P = .022). Potential risk factors for inpatient admission included age, diabetes, hypertension, obstructive sleep apnea, pre-COVID-19 surgery date, and operative duration. CONCLUSION: Outpatient sleeve gastrectomy is safe and efficacious. Administrative support for extended postanesthesia care unit recovery was critical to successful protocol implementation for outpatient sleeve gastrectomy within this large multicenter healthcare system, demonstrating potential applicability nationwide.

National usage of bariatric surgery for class I obesity: an analysis of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program.

BACKGROUND: National and international consensus statements, as well as the National Institutes of Health (NIH), support the use of bariatric surgery for the treatment of class I obesity. Despite this, most payors within the United States limit reimbursement to the outdated 1991 NIH guidelines or a similar adaptation. OBJECTIVES: This study aimed to determine the safety of bariatric surgery in patients with lower BMI compared with standard patients, as well as determine U.S. utilization of bariatric surgery in class I obesity in 2015-2019. SETTING: A retrospective analysis was performed of the 2015-2019 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database. METHODS: Laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass patients were divided into body mass index cohorts: class I obesity (<35 kg/m2) and severe obesity (≥35 kg/m2). Differences in preoperative patient selection and postoperative outcomes were established, and frequency trends were delineated. RESULTS: Analysis included 760,192 surgeries with 8129 (1%) for patients with class I obesity. The patients with class I obesity were older, more commonly female, and with lower American Society of Anesthesiologists (ASA) class, but with higher rates of type 2 diabetes, hyperlipidemia, and gastroesophageal reflux disease (P < .05). Variation was found for operative time, length of stay, 30-day readmission, and composite morbidity. Minimal annual variation was found for bariatric surgeries performed for patients with class I obesity. CONCLUSIONS: The short-term safety of bariatric surgery in patients with class I obesity was corroborated by this study. Despite consensus statements and robust support, rates of bariatric surgery in patients with class I obesity have failed to increase and remain limited to 1%. This demonstrates the impact of the outdated 1991 NIH guidelines regarding access to care for these potentially life-saving surgeries.

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. BACKGROUND: Despite 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.

Association Between Weight Loss and the Risk of Cancer after Bariatric Surgery.

OBJECTIVE: The goal of this study was to determine whether the reduction in cancer risk after bariatric surgery is due to weight loss. METHODS: A retrospective matched cohort study of patients undergoing bariatric surgery was conducted using data from a large integrated health insurance and care delivery system with five sites in four states. The study included 18,355 bariatric surgery subjects and 40,524 nonsurgical subjects matched on age, sex, BMI, site, and Elixhauser comorbidity index. Multivariable Cox proportional hazards models examined the relationship between weight loss at 1 year and incident cancer during up to 10 years of follow-up. RESULTS: The study identified 1,196 cases of incident cancer. The average 1-year postsurgical weight loss was 27% among patients undergoing bariatric surgery versus 1% in matched nonsurgical patients. Percent weight loss at 1 year was significantly associated with a reduced risk of any cancer in adjusted models (HR 0.897, 95% CI: 0.832-0.968, P = 0.005 for every 10% weight loss) while bariatric surgery was not a significant independent predictor of cancer incidence. CONCLUSIONS: Weight loss after bariatric surgery was associated with a lower risk of incident cancer. There was no apparent independent effect of the bariatric surgery itself on cancer risk that was independent of weight loss.

Functional capacity of neutrophils from class III obese patients.

Class III obesity is associated with chronic inflammation and a variety of changes in immune function. Yet surprisingly little was known about the status of neutrophils that represent the first line of immune defense. The aim of this study was to assess key functions of neutrophils from class III obese patients, namely phagocytosis, superoxide production, chemotaxis, and response to endotoxin challenge, and compare their responses with lean controls. Thirty obese patients (BMI 48.8 ± 6.6 kg/m(2)) with comorbidities such as diabetes, hyperlipidemia, high blood pressure, etc. and nine lean (BMI between 20 and 25) subjects were enrolled in the study. Neutrophils from class III obese patients phagocytosed Escherichia coli (E. coli) at similar rates and with adequate numbers of bacteria taken up per cell compared with cells from lean subjects. Neutrophil production of superoxide, which is key to rapid killing of pathogens, showed modest diminution in the class III obese, which increased among patients with BMI >50. Chemotactic activity of neutrophils from class III obese patients was not altered. However, neutrophils from obese subjects showed an increased response to low-dose endotoxin, with concomitant reduced apoptosis and extension of their half-life compared with lean subjects, which suggests possible hyperresponsiveness of these neutrophils. Overall, neutrophil activity was not significantly altered by age, gender, diabetic status, or hyperlipidemia. Collectively, these results suggest that class III obese patients, even with comorbidities, have normal or nearly normal phagocytic, chemotactic, and superoxide generating capacity.