Metabolic surgery for the treatment of type 2 diabetes in patients with BMI lower than 35 kg/m2 : Why caution is still needed.

Bariatric surgery has shifted from being a risky procedure to an evidence-based one, with proven benefits on all-cause mortality, cardiovascular disease, cancer, and diabetes control. The procedure has an overall positive result on type 2 diabetes mellitus (T2DM), with a substantial number of patients achieving disease remission. This has resulted in several studies assessing possible weight-independent effects of bariatric surgery on glycemic improvement, in addition to recommendation of the procedure to patients with class 1 obesity and T2DM, for whom the procedure was classically not indicated, and adoption of a new term, "metabolic surgery," to highlight the overall metabolic benefit of the procedure beyond weight loss. Recently, the Diabetes Surgery Summit (DSS) has included metabolic surgery in its T2DM treatment algorithm. Although the discussion brought by this consensus is highly relevant, the recommendation of metabolic surgery for patients with uncontrolled T2DM and a body mass index of 30 to 35 kg/m2 still lacks enough evidence. This article provides an overall view of the metabolic benefits of bariatric/metabolic surgery in patients with class 1 obesity, compares the procedure against clinical treatment, and presents our rationale for defending caution on recommending the procedure to less obese individuals.

Bariatric surgery in 1119 patients with preoperative body mass index<35 (kg/m(2)): results at 1 year.

BACKGROUND: The use of body mass index (BMI) as the only criterion to indicate bariatric surgery is currently under discussion. There is growing evidence that supports bariatric surgery in carefully selected patients with lower BMI. OBJECTIVES: To report our experience in bariatric surgery in>1000 patients with BMI<35 kg/m(2) and their results at 1 year. SETTING: University hospital (censored). METHODS: A retrospective analysis was performed in patients who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB) or sleeve gastrectomy (SG) with preoperative BMI<35 kg/m(2) from January 2008 to December 2011. Demographic and anthropometric data, preoperative co-morbidities, and perioperative variables were retrieved. Weight loss and co-morbidities progression were analyzed 1 year after surgery and compared among procedures. A P value<.05 was considered significant. RESULTS: We identified 1119 patients: mean age 38.8±11.4, 951 (85%) women, preoperative weight 87.5±9.3 kg and BMI 33.1 (31.9-34.1) kg/m(2). Preoperatively, 11.7% had type 2 diabetes mellitus, 25.9% arterial hypertension, 55.6% insulin resistance, and 53.2% dyslipidemia. In total, 283 patients (25.2%) underwent LRYGB and 836 (74.8%) SG. One year after surgery (follow-up: 66.67%) patients reached 24.5 (22.8-26.4) BMI and the percentage of excess of weight loss (%EWL) was 107.9±36.6%. Diabetes, hypertension, insulin resistance, and dyslipidemia remission/improvement rates were 54/39%, 58/29%, 72/17%, and 54/30%, respectively. CONCLUSIONS: Bariatric surgery in selected class I obesity patients can safely be performed. We have observed good results in terms of weight loss and co-morbidity improvement/remission. Long-term follow-up is required.