Surgical versus medical treatment of type 2 diabetes mellitus in nonseverely obese patients: a systematic review and meta-analysis

Ann Surg. 2015 Mar;261(3):421-9. doi: 10.1097/SLA.0000000000001014.


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.

Bmi (md: -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.

Conclusion: 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.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Bariatric Surgery*
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / surgery*
  • Diabetes Mellitus, Type 2 / therapy
  • Humans
  • Obesity / complications
  • Obesity / surgery*
  • Obesity / therapy
  • Obesity, Morbid