Diabetes kept at bay for at least 10 years through lifestyle changes or metformin

People at high risk of type 2 diabetes can keep the disease at bay for at least 10 years with changes to their lifestyle or treatment with metformin, according to the authors of a new study, which suggests intensive lifestyle interventions are the most effective way of reducing risk.


The study is a follow-up of a three-year diabetes prevention programme (DPP), in which adults at high risk of diabetes we randomised to receive either 850mg metformin twice daily, placebo or intensive lifestyle interventions designed to promote weight loss and physical exercise.

In the DPP study, lifestyle changes were associated with a 58 per cent reduction in diabetes risk and metformin treatment with a 31 per cent reduction, compared with placebo.

A follow-up study published online this week in The Lancet (29 October 2009) tracked the diabetes incidence among 2,766 (88 per cent) of the DPP study participants for a further seven years of treatment (placebo, n=932; metformin, n=924; lifestyle, n=910).

The success of lifestyle interventions in the original DPP study meant that, for ethical reasons, all participants were offered educational materials about lifestyle change and quarterly lifestyle support sessions, in addition to their allocated treatment, for the duration of the follow-up.

Diabetes incidence over the total 10-year study (from the start of the DPP) was reduced by 34 per cent in the lifestyle group (95 per cent confidence interval 24–42) and 18 per cent in the metformin group (CI 7–28), compared with placebo.

During the follow-up period alone (excluding the three years of the DPP study), diabetes incidence did not differ significantly between the three treatment groups.
The authors of the study attribute this to a fall in the incidence of diabetes in both the placebo and metformin groups as a result of those participants receiving lifestyle interventions during the follow-up period.

There may also have been a reduction in the effect of lifestyle interventions, which were of a lower intensity during the follow-up period compared with the DPP study.
“Our results have shown that a reduction in diabetes cumulative incidence by either lifestyle intervention or metformin therapy persists for at least 10 years,” they say, adding that further follow-up is crucial for establishing the benefits of diabetes prevention, and determining the long-term clinical outcomes, including mortality.

The second phase of their long-term DPP follow-up study is due to be completed in 2014.