Promising data for glitazone in diabetes prevention
For people with impaired glucose regulation treatment with rosiglitazone (Avandia), along with lifestyle changes, reduces the risk of progression to type 2 diabetes. This is according to results of the diabetes reduction
assessment with ramipril and rosiglitazone medication (DREAM) trial,
published in The Lancet (2006;368:1096). However, commentators say
that lifestyle interventions should remain the mainstay for prevention
of type 2 diabetes.
Researchers randomised 5,269 adults with impaired glucose tolerance or
impaired fasting glucose and no history of cardiovascular disease to
receive rosiglitazone 8mg daily or placebo for three years. Patients
were concurrently assigned randomly to receive either ramipril 15mg once
daily or placebo so that the independent effect of each intervention
and the combined effect of the two interventions could be evaluated.
In the rosiglitazone group 280 people developed diabetes compared with
658 in the placebo group (hazard ratio 0.38, 95 per cent confidence interval
0.33–0.44; P<0.0001). The reduction in diabetes seen is similar
to that obtained by lifestyle interventions, say the researchers. In
addition, a larger number of people in the rosiglitazone group returned
to normal blood glucose levels than in the placebo group (1,330 versus
798, HR 1.71, 1.57–1.87; P<0.0001).
The difference in incidence of a composite of cardiovascular events in
the two groups was not significant. However, 14 patients in the rosiglitazone
group compared with two in the placebo group developed heart failure
(HR 7.03, 1.60–30.9; P=0.01). The short duration and low rates
of cardiovascular events in the trial prevent reliable conclusions being
drawn about the cardiovascular effects of rosiglitazone, say the researchers. “Further
analyses of these data, together with data from other thiazolidinedione
studies, are indicated to better identify people at risk.”
There was no evidence of an interaction between the ramipril and rosiglitazone
arms of the study.
The authors of an accompanying editorial comment: “Overall, despite
the impressive risk reduction for progression to diabetes, the lack of
data on long-term benefits and side effects, and the high cost of therapy,
mean that health care funders are unlikely to see rosiglitazone as an
appropriate agent for individuals with impaired glucose regulation but
low absolute cardiovascular risk.”
They add that the greater benefits in higher risk individuals would have
to be balanced against the likely increased risk of heart failure.
ACE
inhibitor arm Results from the angiotensin-converting enzyme inhibitor
arm of the DREAM trial were published
online in The New England Journal
of Medicineon
15 September 2006. Researchers found that ramipril did not significantly
reduce the incidence of diabetes or death but did increase return to normal blood
glucose levels. They say that ramipril “may have favourable effects on
glucose metabolism” but further research is needed to clarify this. “For
now, the routine use of ramipril for the express purpose of preventing diabetes
is not indicated,” they conclude. |
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