Review: efficacy of DPP-4 inhibitors is similar to other second line treatments for type 2 diabetes.

Some pills

This systematic review set out to assess the effectiveness of dipeptidyl peptidase-4 (DPP-4) inhibitors compared with other treatments at reducing HbA1c in type 2 diabetes.

Clinical question:

In type 2 diabetes not on insulin, do DPP-4 inhibitors, as compared with alternative treatments, reduce Hba1c?

The comparators included metformin alone and in combination with other oral antidiabetic drugs or basal insulin.  Other outcomes included the proportion of patients achieving HbA1c target of <7%, hypoglycaemic and other adverse events.

The evidence:

The reviewers found 19 studies, involving 13,881 participants.  When they combined the results in a meta-analysis, they concluded that:

  • DPP-4 inhibitors alone were less effective than metformin alone.
  • When added to metformin therapy, DPP-4 inhibitors were less effective than glucagon-like peptide-1 (GLP-1) agonists and had similar efficacy to sulphonylurea and pioglitazone.
  • There was some evidence that DPP-4 inhibitors were better tolerated.

Appraisal hints

Users of this research should consider:

  • The quality of the individual studies:  only three were considered to have low risk of bias.
  • Was there enough data to warrant the conclusions drawn regarding adverse effects?
  • Uncertainty still exists regarding long-term safety.


Karagiannis T, Paschos P, Paletas K, Matthews DR, Tsapas A..  Dipeptidyl peptidase-4 inhibitors for treatment of type 2 diabetes mellitus in the clinical setting: systematic review and meta-analysis. BMJ. 2012 Mar 12;344:e1369. doi: 10.1136/bmj.e1369.

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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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