TZDs may prevent type 2 diabetes

A colourful selection of pills

The Centre for Reviews and Dissemination (CRD) published an appraisal of a systematic review of drug interventions to prevent type 2 diabetes.

Clinical question:

In high risk patients do oral antidiabetic drugs prevent progression to type 2 diabetes?

The scope included thiazolidinediones, biguanides, alpha-glucosidase inhibitors, sulphonylureas, glinides and dipeptidyl peptidase-4 inhibitors.

The evidence:

The reviewers found twenty RCTs with 23,230 participants. Some studies compared the drugs with placebo whilst other used active controls.

Thiazolidinediones were associated with the greatest risk reduction in development of type 2 diabetes compared with control and associated with greater risk reduction than biguanides. Alpha-glucosidase inhibitors and biguanides performed similarly and better than control, while sulphonylureas and glinides provided no significant benefit.

The CRD felt that this was a reliable conclusion based on the evidence in the review.

Appraisal hints:

  • It’s not clear from the abstract or appraisal exactly which interventions were investigated in what combinations, and what co-interventions were provided (such as diet, lifestyle and other education).
  • TZDs are known to have adverse effects.
  • Most of the trials were of low quality and there was a lot of important differences between them.
  • Consider the proven benefits of non-drug interventions in other research.


Phung OJ, Sood NA, Sill BE, Coleman CI. Oral anti-diabetic drugs for the prevention of Type 2 diabetes. Diabetic Medicine 2011; 28(8): 948-964

Get the CRD appraisal

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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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