Laparoscopic Adjustable Gastric Banding in Patients with Body Mass Index Less Than 35 kg/m2 with Weight-Related Comorbidity
Bariatric surgery is an established treatment for morbid obesity in patients with a body mass index (BMI) equal to or greater than 40 kg/m2, or BMI equal to or greater than 35 kg/m2 in the presence of weight-related comorbidities. Some experts have recommended broadening of the eligibility criteria for bariatric surgery, in order to reach more patients who might benefit, but who do not meet the current eligibility criteria. A large proportion of weight-related comorbidities occur in patients with nonmorbid obesity. For example, up to three-quarters of incident cases of diabetes occur in patients with a BMI less than 35 kg/m2. However, the risk/benefit ratio for surgical interventions in an individual patient with nonmorbid obesity is shifted toward less benefit, due to both the lower amount of weight loss expected, as well as the lesser degree of obesity-related comorbidities. The most important outcome measures in studies of bariatric surgery are changes in mortality, weight-related comorbidities, and quality of life. Weight-related comorbidities can include a variety of chronic conditions, such as diabetes, hypertension, hyperlipidemia, osteoarthritis, and obstructive sleep apnea. The most common outcome measure reported is weight loss, which is an intermediate outcome. The benefit of weight loss is intervention-specific because the mechanism and ancillary effects of each intervention are different; therefore, it is not possible to derive an absolute amount of weight loss required to ensure that outcomes are improved. Rather, the risk and benefits of each intervention need to be defined and evaluated separately for that intervention. For the purposes of this Assessment, the primary emphasis will be on the outcomes of weight-related comorbidities, and improvements in these outcomes need to be demonstrated to conclude whether laparoscopic adjustable gastric banding (LAGB) meets the TEC criteria for the nonmorbidly obese patient population. LAGB is a restrictive procedure that works via a prosthetic device that is wrapped around a portion of the stomach. Available gastric bands are saline-filled devices that can be inflated or deflated via a reservoir attached to the band and are accessed through a port without an additional invasive procedure. The Lap-Band® laparoscopic adjustable gastric banding system, Allergan, Irvine, CA, received approval from the U.S. Food and Drug Administration (FDA) in 2001 for treatment of morbidly obese patients. In 2011, approval was granted for treatment of patients with a BMI between 30 and 35 kg/m2 with weight-related comorbidities. Short-term complications of LAGB are well-defined and are expected to be very low. Longer-term complications occur more commonly than short-term complications, but the rates of long-term adverse events are not certain. Previous TEC Assessments have concluded that it is not possible to determine the precise rates of long-term complications from the available data and that it is likely that complications are under-reported in many studies due to incomplete follow-up and a lack of systematic surveillance. Studies published since the last TEC Assessment in 2008 have reported that rates of adverse events continue to increase over longer time periods. A number of studies have reported that treatment failure, defined as inadequate weight loss and/or band removal, can occur in up to half or more of patients treated after 10 years or more of follow-up. The overall objective of this Assessment is to determine whether laparoscopic adjustable gastric banding (LAGB) improves outcomes for patients who have a body mass index (BMI) lower than the current threshold for bariatric surgery. A literature search was performed through MEDLINE® (via PubMed) for the period of January 2008 through April 2012 using the search terms "laparoscopic adjustable gastric banding," "LAGB," "lap-band," and "gastric banding." These terms were cross-referenced with the terms "obesity," "obese," and "overweight." Electronic search was supplemented with a hand search of relevant bibliographies and a "related articles" search of selected citations. Studies were selected that used laparoscopic adjustable gastric banding to treat patients with a BMI less than 35 kg/m2 with weight-related comorbidities, and that were 1) randomized, controlled trials comparing LAGB to nonsurgical treatment or to alternate bariatric surgery procedures; 2) cohort studies or case series that enrolled at least 25 patients; 3) had at least 1 year of follow-up; and 4) reported on one or more relevant outcomes. The health outcomes considered for this Assessment are weight-related comorbidities, including diabetes, hypertension, hyperlipidemia, obstructive sleep apnea, osteoarthritis, gastroesophageal reflux disease, asthma, stress urinary incontinence, and depression. The amount of weight loss is also included in the Assessment, but is not itself considered to result in improvements in health outcomes unless it is linked directly or indirectly to changes in weight-related comorbidities. There is limited evidence available, consisting of one small randomized, controlled trial, one nonrandomized comparative database study, and 5 case series. Quality of evidence by the GRADE method was judged to be moderate for the outcome of weight loss and low for all other outcomes, including mortality, weight-related comorbidities, and quality of life. The single randomized, controlled trial randomized 80 patients to LAGB or an intensive medical program. The trial received a fair rating on formal quality assessment due to a number of methodologic limitations including small size, differential dropout, and lack of blinding. Weight loss was superior for the LAGB group over the course of the trial. At the 2-year final time point, excess weight loss (EWL) was significantly greater for the LAGB group (87.2% vs. 21.8% EWL, p<0.001). The decrease in BMI was also significantly greater for the LAGB group (-7.3 vs. -2.0, p<0.001). The effects on cardiovascular risk factors were variable. The reduction in diastolic blood pressure was significantly greater for the LAGB group, but the reduction in systolic blood pressure was not. High-density lipoprotein (HDL) was significantly increased for the LAGB group, but the changes in total cholesterol, LDL and triglycerides were not significantly different between groups. The plasma glucose level and insulin sensitivity were significantly improved for the LAGB group, but the plasma insulin level was not. The percentage of participants with metabolic syndrome was reduced from 38% to 3% at the completion of the study, compared to a reduction from 38% to 24% in the medical treatment group. Changes in quality-of-life outcomes, as measured by the 8 subscores of the SF-36, were greater numerically for the LAGB group on all scales, with the difference on 4 scales reaching statistical significance (physical function, role physical function, general health, and role emotional function). For the subscales that demonstrated significant differences, the difference between groups ranged from 11–29 points on a 0–100 scale, which is in the range or exceeds the minimal important difference (MID) for these scales. One nonrandomized, comparative study from the Bariatric Outcomes Longitudinal Database (BOLD) compared 1-year outcomes from LAGB with outcomes from gastric bypass in patients with diabetes mellitus and a BMI less than 35 kg/m2. Weight loss, as measured by a change in BMI was greater for the gastric bypass group compared to gastric banding, as was the percent of patients off all diabetic medications. A total of 5 case series met the inclusion criteria for this question. One of these was a prospective study of 149 patients performed by Allergan®, Inc. (Irvine, CA); the other studies were retrospective. The predetermined threshold for success in this study was that 40% or more of patients would achieve at least 30% EWL. This threshold was met, with 83.9% of patients achieving at least 30% EWL at 1 year. Other case series report weight loss, as measured by the percent EWL, that is in the range reported for patients with morbid obesity. The case series report on changes in comorbidities, but only very small numbers of patients are in each category of comorbidity, and the definitions used for improvement or remission are not rigorous. For example, there are a total of 37 patients with diabetes in these 5 studies, and the definitions of remission of diabetes are either patient-reported, or based entirely on whether antidiabetic medications are being used. Adverse events of LAGB are poorly reported in these studies. Some evidence on short-term adverse events is available, such as in the prospective Allergan study. Over the course of the first year, serious adverse events were reported in 7.4% of patients, and reoperations were required in 4.7%. There is very sparse evidence on long-term complications at time points longer than 1 year. Evidence on long-term complications from patients with morbid obesity suggests there are high rates of adverse events such as device migration and removal. In order to determine that health outcomes are improved, it is necessary to demonstrate improvements on measures of morbidity, mortality, and quality of life (QOL). For bariatric surgery, this means that high-quality evidence should demonstrate clinically meaningful improvements in comorbidities such as diabetes and hypertension. The evidence on LAGB for patients with lower BMIs is limited both in quantity and quality. There is only one small randomized, controlled trial, which has methodologic limitations, one nonrandomized comparative study based on registry data, and several case series. Formal quality evaluation of the single randomized, controlled trial resulted in a fair rating, due to the limitations of small size, differential dropout between groups, and lack of blinding. Using the GRADE evaluation, the quality of evidence on the comorbidity outcomes was judged to be low and the quality of the evidence on the weight loss outcomes was judged to be moderate. The evidence is sufficient to determine that weight loss following LAGB is greater than with nonsurgical therapy. All studies report weight loss that is greater than expected with nonsurgical interventions, and which is in the range of excess weight loss reported for morbidly obese patients. This weight loss is maintained at up to 1 to 2 years’ follow-up, but longer follow-up is not available. Direct data on improvement in weight-related comorbidities is lacking. The small randomized, controlled trial reported that there were significant differences in mean diastolic blood pressure, HDL, and serum glucose, but the clinical significance of these changes are not obvious, and this study did not report remission from comorbidities. The single-arm case series report data based on only very small numbers of patients with each individual comorbidity, and use definitions of remission that are often not optimal. As a result, this evidence is not sufficient to conclude that the amount of weight loss is large enough that improvements in weight-related comorbidities can be assumed. There are very little data on quality of life in this population of patients. The randomized, controlled trial reports an improvement in quality of life compared to medical therapy, but this was in a very small number of patients from an unblinded study. One additional case series reported within-group improvements in quality of life. These data are insufficient in quantity to determine whether quality of life is improved following LAGB. The frequency and impact of long-term complications following LAGB is uncertain, and this uncertainty is one of the main reasons why it is difficult to determine whether the benefit of LAGB outweighs the risk for this population. While the short-term safety of LAGB has been well-established, the long-term adverse effects occur at a higher rate and are less well-defined. This high long-term adverse event rate creates uncertainties in attempting to determine the overall risk/ benefit ratio for LAGB. The greatest impact of LAGB may be in patients with diabetes, but the evidence for this population is insufficient in terms of quantity and quality to conclude that a net health benefit is achieved. In addition, the comparative efficacy of different bariatric procedures needs to be considered for this purpose; this question is more fully addressed in a companion TEC Assessment (Vol. 27, No. 2). In conclusion, LAGB for patients with a BMI less than 35 kg/m2 will lead to substantial amounts of weight loss. The percent EWL is roughly similar to that in patients with morbid obesity; however the absolute amount of weight loss is considerably less, and the impact of this degree of weight loss on health outcomes is uncertain. The short-term complication rate is low, but the long-term complication rate is higher and not well defined, particularly for the population of patients with nonmorbid obesity. The combination of the uncertain benefit of weight loss, combined with a high long-term adverse event rate, leads to uncertainty in the overall risk/benefit ratio for this procedure. For these reasons, the evidence does not permit conclusions on whether LAGB improves health outcomes for patients with a BMI less than 35 kg/m2. Based on the available evidence, the Blue Cross and Blue Shield Medical Advisory Panel made the following judgments about whether laparoscopic adjustable gastric banding (LAGB) meets the Blue Cross and Blue Shield Association Technology Evaluation Center (TEC) criteria for patients with a BMI less than 35 kg/m2. 1. The technology must have final approval from the appropriate governmental regulatory bodies. LAGB has been FDA-approved since 2001 for patients with a BMI greater than 40 kg/m2, or a BMI of equal to or greater than 35–40 kg/m2 in the presence of weight-related comorbidities. In February 2011, the FDA granted approval for LAGB in patients with a BMI of 30–35 kg/m2 in the presence of at least one weight-related comorbidity. The FDA labeling indicates that this procedure should be reserved for patients who have been unsuccessful in achieving weight loss by nonsurgical methods and for patients who are at the highest risk for weight-related complications. 2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes. The scientific evidence permits conclusions that LAGB leads to substantial weight loss for patients with lower BMIs. The percent EWL is as high, or higher, than that reported for morbidly obese patients. It is also possible to conclude that the amount of weight loss following LAGB is greater than that seen with nonsurgical treatment. The available evidence is insufficient to determine whether LAGB leads to favorable changes in weight-related comorbidities. The evidence is not of adequate quantity or quality to form conclusions on this question. The magnitude of benefit appears to be greatest for patients with diabetes, but this is based on a very small number of patients (n=37) and using definitions of diabetes remission that are not rigorous. For comorbidities other than diabetes, the evidence does not consistently report that improvements occur following LAGB. For these reasons, the evidence is insufficient to permit conclusions on the effect of LAGB on health outcomes for this population.Executive Summary
Background
Assessment Objective
Search Methods
Study Selection
Main Results
Author’s Conclusions and Comments
3. The technology must improve the net health outcome; and
4. The technology must be as beneficial as any established alternatives.
The evidence is not sufficient to permit conclusions on the effect of LAGB on health outcomes; therefore, it is not possible to conclude that the net health outcome is improved, nor that LAGB is as beneficial as established alternatives in nonmorbidly obese patients.
5. The improvement must be attainable outside the investigational settings.
Whether LAGB improves the net health outcome for patients with a BMI of less than 35 kg/m2 with obesity-related comorbidities has not been demonstrated in the investigational setting.
Based on the above, laparoscopic adjustable gastric banding for the treatment of patients with BMI less than 35 kg/m2 with weight-related comorbidities does not meet the TEC criteria.
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adjustable; adverse effects; AEs; anastomosis; anti-incretin; appetite; asthma; band; banding; biliopancreatic; BMI; body mass index; BPD; caloric intake; case series; Class I; Class II; Class III; comorbidity; complications; controlled; depression; diabetes; diabetic; diversion; DM; duodenal; duodenal switch; duodenal-jejunal exclusion; gastrectomy; gastric; gastric bypass; gastric resection; gastroesophageal reflux disease; gastrojejunostomy; ghrelin; GLP-1; glycosylated; hemoglobin a1c; hyperlipidemia; hypertension; ileal interposition; incretin; insulin; LAGB; laparoscopic gastric banding; L-cell peptides; lifestyle; malabsorption; mellitus; meta-analysis; metabolic; metabolic syndrome; morbid; morbidly; National Health and Nutrition Examination Survey; NHANES; nonsurgical; obese; obesity; observational; obstructive sleep apnea; osteoarthritis; overweight; postprandial; randomized; RCTs; remission; resistance; RNY; roux en y; sleeve; stress urinary incontinence; systematic review; trial; type 2; type II;
