Bariatric surgery improved HbA1c in obese type 2 diabetes with BMI < 35

A gastric band

A number of recent studies have found that bariatric surgery can improve diabetes or even reverse it.  This meta-analysis looked at its use in people with type 2 diabetes who are obese but not severely obese.

Clinical question:

In obese type 2 diabetics with BMI < 35, does bariatric surgery reduce improve glycaemic control?

The evidence:

The reviewers found thirteen trials involving 357 patients.  According to their meta-analysis, bariatric surgery significantly reduced BMI and cholesterol and enabled 80% of patients to reach their target HbA1c.  They also found that the benefits were sustained after prolonged period of foll0w-up.

Appraisal hints:

Users of this research should consider:

  • Did the reviewers make sufficient efforts to find all of the relevant evidence?
  • Was there a comparison intervention?  What outcomes would we expect from conventional treatment?
  • Did they assess the quality of the studies and take account of the risk of bias?
  • Was there any important heterogeneity between the studies?
  • Although the reviewers did not find any reports of post-operative mortality, there were other major adverse effects.


Li Q, Chen L, et al. Metabolic effects of bariatric surgery in type 2 diabetic patients with body mass index < 35 kg/m2. Diabetes Obes Metab. 2012 Mar;14(3):262-70.

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I am an information scientist with an interest in making knowledge from systematic research more accessible to people who need it. This means you. I've been attempting this in the area of Evidence-Based Health Care since 1995. So far the results have been mixed. For some reason we expected busy clinicians to search databases and appraise papers instead of seeing patients. We also expected publishers to make the research freely available to the people who paid for it.. Ha! Hence The National Elf service.

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