title: Surgical versus medical treatment of type 2 diabetes mellitus in nonseverely obese patients: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To compare surgical versus medical treatment of type 2 diabetes mellitus (T2DM) remission and comorbidities in patients with a body mass index (BMI) less than 35 kg/m2.
  
  
  BACKGROUND
  Obesity surgery can achieve remission of T2DM and its comorbidities. Metabolic surgery has been proposed as a treatment option for diabetic patients with BMI less than 35 kg/m2 but the efficacy of metabolic surgery has not been conclusively determined.
  
  
  METHODS
  A systematic literature search identified randomized (RCT) and nonrandomized comparative observational clinical studies (OCS) evaluating surgical versus medical T2DM treatment in patients with BMI less than 35 kg/m2. The primary outcome was T2DM remission. Additional analyses comprised glycemic control, BMI, HbA1c level, remission of comorbidities, and safety. Random effects meta-analyses were calculated and presented as weighted odds ratio (OR) or mean difference (MD) with 95% confidence intervals (95% CI).
  
  
  RESULTS
  Five RCTs and 6 OCSs (706 total T2DM patients) were included. Follow-up ranged from 12 to 36 months. Metabolic surgery was associated with a higher T2DM remission rate (OR: 14.1, 95% CI: 6.7-29.9, P < 0.001), higher rate of glycemic control (OR: 8.0, 95% CI: 4.2-15.2, P < 0.001) and lower HbA1c level (MD: -1.4%, 95% CI -1.9% to -0.9%, P < 0.001) than medical treatment.
  -5.5 kg/m2, 95% CI: -6.7 to -4.3 kg/m2, P < 0.001), rate of arterial hypertension (OR: 0.25, 95% CI: 0.12-0.50, P < 0.001) and dyslipidemia (OR: 0.21, 95% CI: 0.10-0.44, P < 0.001) were lower after surgery.
  
  
  CONCLUSIONS
  Metabolic surgery is superior to medical treatment for short-term remission of T2DM and comorbidities. Further RCTs should address the long-term effects on T2DM complications and mortality.
authors.affiliation: *Department of General, Visceral and Transplantation Surgery †Institute of Medical Biometry and Informatics ‡Study Center of the German Surgical Society (SDGC) §Department of Internal Medicine I and Clinical Chemistry, University of Heidelberg, Heidelberg, Germany ¶Department of Surgery, Kantonsspital St Gallen, Rorschacher Strasse 95, CH-9007 St Gallen, Switzerland.
authors.forename: Beat P
authors.initials: BP
authors.lastname: Müller-Stich
authors.forename: Jonas D
authors.initials: JD
authors.lastname: Senft
authors.forename: René
authors.initials: R
authors.lastname: Warschkow
authors.forename: Hannes G
authors.initials: HG
authors.lastname: Kenngott
authors.forename: Adrian T
authors.initials: AT
authors.lastname: Billeter
authors.forename: Gianmatteo
authors.initials: G
authors.lastname: Vit
authors.forename: Stefanie
authors.initials: S
authors.lastname: Helfert
authors.forename: Markus K
authors.initials: MK
authors.lastname: Diener
authors.forename: Lars
authors.initials: L
authors.lastname: Fischer
authors.forename: Markus W
authors.initials: MW
authors.lastname: Büchler
authors.forename: Peter P
authors.initials: PP
authors.lastname: Nawroth
mesh_terms: D050110:Bariatric Surgery; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000601:surgery* / Q000628:therapy; D006801:Humans; D009765:Obesity / Q000150:complications / Q000601:surgery* / Q000628:therapy; D009767:Obesity, Morbid