Review of the key results from the Swedish Obese Subjects (SOS) trial – a prospective controlled intervention study of bariatric surgery

Abstract

Abstract. L. Sj€ ostr€ om (The Sahlgrenska Academy, The University of Gothenburg, Gothenburg, Sweden). Review of the key results from the Swedish Obese Subjects (SOS) trial -a prospective controlled intervention study of bariatric surgery (Review). J Intern Med 2013; 273: 219-234.Obesity is a risk factor for diabetes, cardiovascular disease events, cancer and overall mortality. Weight loss may protect against these conditions, but robust evidence for this has been lacking. The Swedish Obese Subjects (SOS) study is the first long-term, prospective, controlled trial to provide information on the effects of bariatric surgery on the incidence of these objective endpoints. The SOS study involved 2010 obese subjects who underwent bariatric surgery [gastric bypass (13%), banding (19%) and vertical banded gastroplasty (68%)] and 2037 contemporaneously matched obese control subjects receiving usual care. The age of participants was 37-60 years and body mass index (BMI) was ! 34 kg m À2 in men and ! 38 kg m À2 in women. Here, we review the key SOS study results published between 2004 and 2012. Follow-up periods varied from 10 to 20 years in different reports. The mean changes in body weight after 2, 10, 15 and 20 years were À23%, À17%, À16% and À18% in the surgery group and 0%, 1%, À1% and À1% in the control group respectively. Compared with usual care, bariatric surgery was associated with a long-term reduction in overall mortality (primary endpoint) [adjusted hazard ratio (HR) = 0.71, 95% confidence interval (CI) 0.54-0.92; P = 0.01] and decreased incidences of diabetes (adjusted HR=0.17; P < 0.001), myocardial infarction (adjusted HR = 0.71; P = 0.02), stroke (adjusted HR=0.66; P = 0.008) and cancer (women: adjusted HR = 0.58; P = 0.0008; men: n.s.]. The diabetes remission rate was increased severalfold at 2 years [adjusted odds ratio (OR) = 8.42; P < 0.001] and 10 years (adjusted OR = 3.45; P < 0.001). Whereas high insulin and/or high glucose at baseline predicted favourable treatment effects, high baseline BMI did not, indicating that current selection criteria for bariatric surgery need to be revised.

Medication and nutritional supplement use before and after bariatric surgery

“…12 The quick and sustained improvement in glucose homeostasis that this procedure provides has made it the gold-standard metabolic procedure and treatment for diabetic patients with morbid obesity. 13 Comorbidity reductions are reflected in diminished drug use during the postoperative period, and discontinuation of drug therapy for some diseases, thus resulting in reduced expenditure on drugs and other healthcare services. 10,[14][15][16][17][18] In addition, bariatric surgery extends survival, decreases occurrences of cardiovascular events and is also associated with greater reduction of mortality due to cardiovascular diseases, myocardial infarction, stroke, diabetes and cancer, in comparison with obese individuals who do not undergo this surgery.…”

Surgery in the treatment of type 2 diabetes mellitus

“…Weight loss can restore insulin sensitivity, and patients can even achieve remission of T2DM. In Swedish obese Subjects (SoS) study, weight loss by conventional medical therapy was associated with 21.0% remission rate of T2DM at 2 years and 12.0% at 10 years (17). However, weight maintenance after conventional medical therapy is a problem, and most of the patients experience weight regain (18,19).…”

Protocol for: The Use of Intra-Gastric Balloons as an Adjunct to a Lifestyle Support Programme to Promote Weight Loss in Severely Obese Adolescents

“…The National Institute for Health and Clinical Excellence (NICE) presents treatment guidelines for overweight and obese children and young people, emphasizing the importance of lifestyle interventions focusing on diet control, physical activity and behavioural change all being delivered within a multi-disciplinary framework [10,11]. Yet, for many adolescents whose Body Mass Index (BMI) place them in the severely obese bracket (i.e.…”