Despite patient eligibility for bariatric surgery expanding over the last decade and its safety and effectiveness even further established in clinical studies and professional guidelines, relatively few patients with a body mass index (BMI) below 35 actually get the surgery in any given year, according to two new studies presented at the American Society for Metabolic and Bariatric Surgery (ASMBS) 2023 Annual Scientific Meeting.
In the first study, ‘Bariatric Surgery for Low BMI Patients, a Registry Study’, investigators from New Jersey Bariatric Center, examined the outcomes of weight loss in patients with a BMI≥35 or BMI≥30 with comorbidities that had bariatric surgery. In total, 30 patients who underwent surgery (sleeve gastrectomy vs roux-en-Y gastric bypass) were enrolled in the study. Data was analyzed from 2017-2021 and 77% (23/30) of patients who were enrolled had beyond six months of follow-up data available. Patients that had less than six months of data for analysis were excluded. Change in BMI, body weight, and excess body weight loss percentage (EBWL%) were analysed.
The mean BMI at commencement was 33.47 and at the time of data analysis, mean BMI was 26.56. Mean excess percentage weight loss was 55.03%. Nearly 60% of patients lost a minimum of 50% of their excess body weight. Nine of sixteen patients (56.25%) with comorbidities had improvement or resolution. There were no complications or mortalities for study participants.
“Our study shows significant weight loss and health benefits, as well as the safety and efficacy of the gastric bypass and gastric sleeve procedures, for this patient population,” said Dr Ajay Goyal, principal investigator and bariatric surgeon at New Jersey Bariatric Center. “Often by the time a patient qualifies for bariatric surgery their weight-related medical conditions such as diabetes and hypertension are severe. By expanding access to bariatric surgery to patients with a lower BMI with obesity-related illnesses, patients can halt the progression, and in some cases resolve, significant and uncontrolled weight-related chronic diseases through weight loss.”
In the second study, ‘Has Expansion of Guidelines on Bariatric Surgery for Class 1 Obesity Impacted Practice? National Trends and Outcomes in Class 1 Obesity (BMI 30-35 kg/m2) from 2015 to 2021’, researchers at the University of Southern California (USC) analysed national trends in MBS for class 1 obesity (C1O) during this time period and evaluated 30-day outcomes using univariate and multivariate analyses.
“Despite widespread acceptance of bariatric surgery as the most effective treatment for obesity, significant barriers to treatment still exist across the spectrum of obesity and in particular, those on the lower end,” said study co-author, Dr Paul Wisniowski, a surgical resident at University of Southern California. “Generally, the earlier the intervention on obesity or any disease, the better the outcome. Patients need not wait until their obesity and related conditions become severe before seeking bariatric surgery.”
Data was obtained from the Metabolic Bariatric Surgery Accreditation Quality Improvement Program (MBSAQIP), which maintains a database of inpatient and outpatient bariatric surgery procedures performed in accredited centres throughout the US and Canada.
The study included 38,669 (3.5%) patients with C1O and 1,067,094 (96.5%) patients with BMI>35. Patients with C1O were younger 49y vs 44y (p<0.01), and predominantly white 76% vs 70% (p<0.01). The trends in MBS for C1O showed no significant increase indexed to total MBS cases, remaining at approximately 3.5% of all MBS procedures per year (p=NS). Trends in utilisation of MBS for C1O with and without diabetes showed similar minimal change over time.
The utilisation of sleeve gastrectomy increased 6%, adjustable gastric band decreased 5.6% and robotic use increased 15% during the study period (p<0.01). On univariate analysis C1O had fewer superficial infections, more reoperations and decreased mortality (all p<0.01), but no difference in these outcomes on multivariate regression.
“Despite the expansion of guidelines supporting MBS in patients with class 1 obesity, there has been little corresponding increase in utilization in this population in recent years,” the authors concluded. “Further analysis is needed to identify patient, provider, and system level factors that may be serving as barriers to increased access to MBS in this population.
In 2018, the ASMBS updated its position on Class 1 obesity stating “bariatric surgery should be offered as an option” and access “should not be denied solely based on this outdated threshold”, referring to the prior minimum
BMI requirement of 35. It further notes that current nonsurgical treatments “are often ineffective at achieving major, long-term weight reduction and resolution of co-morbidities.”
“Professional guidelines and increasing data support bariatric surgery for patients beginning at BMI 30, which is a tipping point for disease progression. Now it needs to happen in the real world,” said Dr Teresa LaMasters, ASMBS President and a bariatric surgeon and board-certified obesity medicine physician, who was not involved with the studies. “We encourage greater consideration of this important treatment option earlier in the disease process.”