Severe obesity and its related diseases, such as type 2 diabetes, hypertension, dyslipidemia, and sleep apnea, are very common in the United States, but currently very few patients with these ...conditions choose to undergo bariatric surgery. Summaries of the expanding evidence for both the benefits and risks of bariatric surgery are needed to better guide shared decision-making conversations.
There are approximately 252 000 bariatric procedures (per 2018 numbers) performed each year in the US, of which an estimated 15% are revisions. The 1991 National Institutes of Health guidelines recommended consideration of bariatric surgery in patients with a body mass index (calculated as weight in kilograms divided by height in meters squared) of 40 or higher or 35 or higher with serious obesity-related comorbidities. These guidelines are still widely used; however, there is increasing evidence that bariatric procedures should also be considered for patients with type 2 diabetes and a body mass index of 30 to 35 if hyperglycemia is inadequately controlled despite optimal medical treatment for type 2 diabetes. Substantial evidence indicates that surgery results in greater improvements in weight loss and type 2 diabetes outcomes, compared with nonsurgical interventions, regardless of the type of procedures used. The 2 most common procedures used currently, the sleeve gastrectomy and gastric bypass, have similar effects on weight loss and diabetes outcomes and similar safety through at least 5-year follow-up. However, emerging evidence suggests that the sleeve procedure is associated with fewer reoperations, and the bypass procedure may lead to more durable weight loss and glycemic control. Although safety is a concern, current data indicate that the perioperative mortality rates range from 0.03% to 0.2%, which has substantially improved since early 2000s. More long-term randomized studies are needed to assess the effect of bariatric procedures on cardiovascular disease, cancer, and other health outcomes and to evaluate emerging newer procedures.
Modern bariatric procedures have strong evidence of efficacy and safety. All patients with severe obesity-and especially those with type 2 diabetes-should be engaged in a shared decision-making conversation about the risks and benefits of surgery compared with continuing usual medical and lifestyle treatment, and the decision about surgery should be driven primarily by informed patient preferences.
To determine whether bariatric surgery is associated with a lower risk of cancer.
Obesity is strongly associated with many types of cancer. Few studies have examined the relationship between ...bariatric surgery and cancer risk.
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.
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.
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 induces significant weight loss for severely obese patients, but there is limited evidence of the durability of weight loss compared with nonsurgical matches and across bariatric ...procedures.
To examine 10-year weight change in a large, multisite, clinical cohort of veterans who underwent Roux-en-Y gastric bypass (RYGB) compared with nonsurgical matches and the 4-year weight change in veterans who underwent RYGB, adjustable gastric banding (AGB), or sleeve gastrectomy (SG).
In this cohort study, differences in weight change up to 10 years after surgery were estimated in retrospective cohorts of 1787 veterans who underwent RYGB from January 1, 2000, through September 30, 2011 (573 of 700 eligible 81.9% with 10-year follow-up), and 5305 nonsurgical matches (1274 of 1889 eligible 67.4% with 10-year follow-up) in mixed-effects models. Differences in weight change up to 4 years were compared among veterans undergoing RYGB (n = 1785), SG (n = 379), and AGB (n = 246). Data analysis was performed from September 9, 2014, to February 12, 2016.
Bariatric surgical procedures and usual care.
Weight change up to 10 years after surgery through December 31, 2014.
The 1787 patients undergoing RYGB had a mean (SD) age of 52.1 (8.5) years and 5305 nonsurgical matches had a mean (SD) age of 52.2 (8.4) years. Patients undergoing RYGB and nonsurgical matches had a mean body mass index of 47.7 and 47.1, respectively, and were predominantly male (1306 73.1% and 3911 73.7%, respectively). Patients undergoing RYGB lost 21% (95% CI, 11%-31%) more of their baseline weight at 10 years than nonsurgical matches. A total of 405 of 564 patients undergoing RYGB (71.8%) had more than 20% estimated weight loss, and 224 of 564 (39.7%) had more than 30% estimated weight loss at 10 years compared with 134 of 1247 (10.8%) and 48 of 1247 (3.9%), respectively, of nonsurgical matches. Only 19 of 564 patients undergoing RYGB (3.4%) regained weight back to within an estimated 5% of their baseline weight by 10 years. At 4 years, patients undergoing RYGB lost 27.5% (95% CI, 23.8%-31.2%) of their baseline weight, patients undergoing AGB lost 10.6% (95% CI, 0.6%-20.6%), and patients undergoing SG lost 17.8% (95% CI, 9.7%-25.9%). Patients undergoing RYGB lost 16.9% (95% CI, 6.2%-27.6%) more of their baseline weight than patients undergoing AGB and 9.7% (95% CI, 0.8%-18.6%) more than patients undergoing SG.
Patients in the Veterans Administration health care system lost substantially more weight than nonsurgical matches and sustained most of this weight loss in the long term. Roux-en-Y gastric bypass induced significantly greater weight loss among veterans than SG or AGB at 4 years. These results provide further evidence of the beneficial association between surgery and long-term weight loss that has been demonstrated in shorter-term studies of younger, predominantly female populations.
This review summarizes recent evidence related to the safety, efficacy, and metabolic outcomes of bariatric surgery to guide clinical decision making. Several short term randomized controlled trials ...have demonstrated the effectiveness of bariatric procedures for inducing weight loss and initial remission of type 2 diabetes. Observational studies have linked bariatric procedures with long term improvements in body weight, type 2 diabetes, survival, cardiovascular events, incident cancer, and quality of life. Perioperative mortality for the average patient is low but varies greatly across subgroups. The incidence of major complications after surgery also varies widely, and emerging data show that some procedures are associated with a greater risk of substance misuse disorders, suicide, and nutritional deficiencies. More research is needed to enable long term outcomes to be compared across various procedures and subpopulations, and to identify those most likely to benefit from surgical intervention. Given uncertainties about the balance between the risks and benefits of bariatric surgery in the long term, the decision to undergo surgery should be based on a high quality shared decision making process.
This retrospective cohort study examined whether bariatric surgery is associated with reduced risk of breast cancer among pre- and postmenopausal women.
Obesity is associated with increased risk of ...breast cancer, but the impact of weight loss on breast cancer risk has been difficult to quantify.
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.
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).
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.
Aims/hypothesis
Mounting evidence indicates that Roux-en-Y gastric bypass (RYGB) ameliorates type 2 diabetes, but randomised trials comparing surgical vs nonsurgical care are needed. With a ...parallel-group randomised controlled trial (RCT), we compared RYGB vs an intensive lifestyle and medical intervention (ILMI) for type 2 diabetes, including among patients with a BMI <35 kg/m
2
.
Methods
By use of a shared decision-making recruitment strategy targeting the entire at-risk population within an integrated community healthcare system, we screened 1,808 adults meeting inclusion criteria (age 25–64, with type 2 diabetes and a BMI 30–45 kg/m
2
). Of these, 43 were allocated via concealed, computer-generated random assignment in a 1:1 ratio to RYGB or ILMI. The latter involved ≥45 min of aerobic exercise 5 days per week, a dietitian-directed weight- and glucose-lowering diet, and optimal diabetes medical treatment for 1 year. Although treatment allocation could not be blinded, outcomes were determined by a blinded adjudicator. The primary outcome was diabetes remission at 1 year (HbA
1c
<6.0% <42.1 mmol/mol, off all diabetes medicines).
Results
Twenty-three volunteers were assigned to RYGB and 20 to ILMI. Of these, 11 withdrew before receiving any intervention. Hence 15 in the RYGB group and 17 in the IMLI group were analysed throughout 1 year. The groups were equivalent regarding all baseline characteristics, except that the RYGB cohort had a longer diabetes duration (11.4 ± 4.8 vs 6.8 ± 5.2 years,
p
= 0.009). Weight loss at 1 year was 25.8 ± 14.5% vs 6.4 ± 5.8% after RYGB vs ILMI, respectively (
p
< 0.001). The ILMI exercise programme yielded a 22 ± 11% increase in
V
⋅
O
2
max
(
p
<0.0001), whereas
V
⋅
O
2
max
after RYGB was unchanged. Diabetes remission at 1 year was 60.0% with RYGB vs 5.9% with ILMI (
p
= 0.002). The HbA
1c
decline over 1 year was only modestly more after RYGB than ILMI: from 7.7 ± 1.0% (60.7 mmol/mol) to 6.4 ± 1.6% (46.4 mmol/mol) vs 7.3 ± 0.9% (56.3 mmol/mol) to 6.9 ± 1.3% (51.9 mmol/mol), respectively (
p
= 0.04); however, this drop occurred with significantly fewer or no diabetes medications after RYGB. No life-threatening complications occurred.
Conclusions/interpretation
Compared with the most rigorous ILMI yet tested against surgery in a randomised trial, RYGB yielded greater type 2 diabetes remission in mild-to-moderately obese patients recruited from a well-informed, population-based sample.
Trial registration
:
ClinicalTrials.gov NCT01295229
The clinical evidence base demonstrating bariatric surgery's health benefits is much larger than it was when the National Institutes of Health last held a consensus panel in 1991. Still, it remains ...unclear whether ongoing studies will address critical questions about long-term complication rates and the sustainability of weight loss and comorbidity control.
To summarize findings from a multidisciplinary workshop convened in May 2013 by the National Institute of Diabetes and Digestive and Kidney Diseases and the National Heart, Lung, and Blood Institute. The workshop aimed to summarize the current state of knowledge of bariatric surgery, review research findings on the long-term outcomes of bariatric surgery, and establish priorities for future research directions.
The evidence presented at the workshop was selected by the planning committee for both its quality and duration of follow-up. The data review emphasized randomized clinical trials and large observational studies with long-term follow-up, with or without a control group.
Several small randomized clinical trials showed greater weight loss and type 2 diabetes mellitus remission compared with nonsurgical treatments within the first 2 years of follow-up after bariatric surgery. Large, long-term observational studies have shown durable (>5 years) weight loss, diabetes, and lipid improvements with bariatric surgery. Still unclear are predictors of outcomes, long-term complications, long-term survival, microvascular and macrovascular events, mental health outcomes, and costs. The studies needed to address these knowledge gaps would be expensive and logistically difficult to perform.
High-quality evidence shows that bariatric surgical procedures result in greater weight loss than nonsurgical treatments and are more effective at inducing initial type 2 diabetes mellitus remission in obese patients. More information is needed about the long-term durability of comorbidity control and complications after bariatric procedures and this evidence will most likely come from carefully designed observational studies.
The prevalence of obesity continues to rise around the world, driving up the need for effective and durable treatments. The field of metabolic/bariatric surgery has grown rapidly in the past 25 ...years, with observational studies and randomized controlled trials investigating a broad range of long term outcomes. Metabolic/bariatric surgery results in durable and significant weight loss and improvements in comorbid conditions, including type 2 diabetes. Observational studies show that metabolic/bariatric surgery is associated with a lower incidence of cardiovascular events, cancer, and death. Weight regain is a risk in a fraction of patients, and an association exists between metabolic/bariatric surgery and an increased risk of developing substance and alcohol use disorders, suicidal ideation/attempts, and accidental death. Patients need lifelong follow-up to help to reduce the risk of these complications and other nutritional deficiencies. Different surgical procedures have important differences in risks and benefits, and a clear need exists for more long term research about less invasive and emerging procedures. Recent guidelines for the treatment of obesity and metabolic conditions have been updated to reflect this growth in knowledge, with an expansion of eligibility criteria, particularly people with type 2 diabetes and a body mass index between 30.0 and 34.9.
Accumulating evidence suggests that bariatric surgery improves survival among patients with severe obesity, but research among veterans has shown no evidence of benefit.
To examine long-term survival ...in a large multisite cohort of patients who underwent bariatric surgery compared with matched control patients.
In a retrospective cohort study, we identified 2500 patients (74% men) who underwent bariatric surgery in Veterans Affairs (VA) bariatric centers from 2000-2011 and matched them to 7462 control patients using sequential stratification and an algorithm that included age, sex, geographic region, body mass index, diabetes, and Diagnostic Cost Group. Survival was compared across patients who underwent bariatric surgery and matched controls using Kaplan-Meier estimators and stratified, adjusted Cox regression analyses.
Bariatric procedures, which included 74% gastric bypass, 15% sleeve gastrectomy, 10% adjustable gastric banding, and 1% other.
All-cause mortality through December 2013.
Surgical patients (n = 2500) had a mean age of 52 years and a mean BMI of 47. Matched control patients (n = 7462) had a mean age of 53 years and a mean BMI of 46. At the end of the 14-year study period, there were a total of 263 deaths in the surgical group (mean follow-up, 6.9 years) and 1277 deaths in the matched control group (mean follow-up, 6.6 years). Kaplan-Meier estimated mortality rates were 2.4% at 1 year, 6.4% at 5 years, and 13.8% at 10 years for surgical patients; for matched control patients, 1.7% at 1 year, 10.4% at 5 years, and 23.9% at 10 years. Adjusted analysis showed no significant association between bariatric surgery and all-cause mortality in the first year of follow-up (adjusted hazard ratio HR, 1.28 95% CI, 0.98-1.68), but significantly lower mortality after 1 to 5 years (HR, 0.45 95% CI, 0.36-0.56) and 5 to 14 years (HR, 0.47 95% CI, 0.39-0.58). The midterm (>1-5 years) and long-term (>5 years) relationships between surgery and survival were not significantly different across subgroups defined by diabetes diagnosis, sex, and period of surgery.
Among obese patients receiving care in the VA health system, those who underwent bariatric surgery compared with matched control patients who did not have surgery had lower all-cause mortality at 5 years and up to 10 years following the procedure. These results provide further evidence for the beneficial relationship between surgery and survival that has been demonstrated in younger, predominantly female populations.
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