Prevention of diabetes: Lifestyle and metformin are the way forwardBMJ 2006; 333 doi: http://dx.doi.org/10.1136/bmj.333.7574.918-d (Published 26 October 2006) Cite this as: BMJ 2006;333:918
EDITOR—The concern expressed by Heneghan et al1 that drug treatment to prevent diabetes may not be as attractive as it first seems, may be justified for rosiglitazone but is not for metformin, which is effective, safe, and cheap.
While the 31% reduction in new cases of diabetes with metformin in the Diabetes Prevention Program (DPP)2 seems unimpressive compared with the lifestyle groups' 58%, in certain subgroups metformin was more impressive. Reduction of incidence of diabetes in the young (under 45) was 44% and in the obese (BMI > 35) 53% (lifestyle 48% and 51%, respectively). It would be interesting to see an analysis of the “young and obese.”
Moreover, subjects in the programme were highly selected to be appropriate for a trial of intensive lifestyle modification. For example, smoking prevalence was only 7%. We are unlikely to see the same gains from lifestyle intervention in the real world.
As Heneghan et al point out,1 rosiglitazone was associated with a non-significant 37% increase in cardiovascular endpoints in the DREAM study3; metformin seems safe. The UKPDS4 showed a 36% reduction for all-cause mortality, and 42% for diabetes related death with metformin in the obese (BMI above 25.6).
Regarding cost, lifestyle intervention in the Diabetes Prevention Program cost $2780 (£1486; €2213) / person over three years. Cost of drug treatment with 8 mg rosiglitazone/day, (as per DREAM) for three years would be nearly £2000 using the drug tariff, but metformin 850 mg twice daily (as per the programme) would cost less than £40. Furthermore, the cost effectiveness analysis of the UKPDS showed overall cost savings from reduced hospital costs with metformin.
Although the UKPDS is considered a diabetes study, the entry criterion was a fasting glycaemia above 6.0 mmol/l, or what we now consider as impaired fasting glycaemia. We should be prepared to follow the clear evidence base and prescribe metformin to any overweight patient with abnormal fasting glucose, after three months of lifestyle advice.
Competing interests None declared.