Lifestyle changes aimed at preventing type 2 diabetes were cost-effective for improving quality of life.

A recent follow-up of a randomised trial looked at the long-term costs of different ways of preventing type 2 diabetes in people with impaired glucose tolerance.

Clinical question:

In people with impaired glucose tolerance and fasting hyperglycaemia, are lifestyle interventions, as compared to metformin or usual care, cost-effective?

This paper reports the costs and quality of life outcomes (as Quality-Adjusted Life Years or QALYs) from the long-term follow-up.

The evidence:

The data was from 2,766 patients who completed the 4-year Diabetes Prevention Program (DPP) trial that finished in 2001 and went on to enrol in a “maintenance” phase.

The lifestyle intervention comprised a core “curriculum” of diet and exercise interventions, supplemented by individualised sessions and group reinforcement sessions.

For 10 years, direct non-medical and medical costs were calculated for each treatment arm.  These were collated against the QALYs for each group to calculate an incremental cost-effectiveness ratio.

These were:

  1. Lifestyle vs metformin:  The cost per QALY gained was $13,420
  2. Lifestyle vs placebo:  The cost per QALY was $10,037
  3. Metformin vs placebo: Metformin was cost-saving when compared with the placebo group.

Note that although metformin was cost-saving when compared with placebo, the lifestyle interventions were associated with better quality of life.

Appraisal hints

  • Note that because of the way patients were recruited, the sample was not properly randomised at inception.  Only 88% of the DPP participants went on to the maintenance phase.
  • It seems likely that the participants in each group received co-interventions.
  • Costs were based on patients at an early stage of disease and may be underestimates when translated to a broader population.
  • Is the lifestyle intervention deliverable in your setting?


The full text is available from Diabetes Care:

The Diabetes Prevention Program Research Group.  The 10-Year Cost-Effectiveness of Lifestyle Intervention or Metformin for Diabetes Prevention: An intent-to-treat analysis of the DPP/DPPOS.  Diabetes Care April 2012 vol. 35 no. 4 723-730

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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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