Metformin's Diabetes Preventive Effects Persist
After Drug Withdrawal
Metformin prevented diabetes a substantial 25% after
withdrawal.
The benefits of metformin in preventing diabetes
appear to persist in some patients after the drug
has been discontinued, according to a report in the
April issue of Diabetes Care.
In the Diabetes Prevention Program (DPP), metformin
significantly reduced (by 31%) the risk of diabetes
in patients with impaired glucose tolerance, the
authors explain, but whether these effects were
transient or sustained was not determined.
The Diabetes Prevention Program Research Group
repeated the oral glucose tolerance test 1 to 2
weeks after
discontinuation of medication (metformin or placebo)
in 1274 patients in the original study who had
not developed diabetes by the end of the trial.
After the washout period, the authors report, the
percentage of diabetes increased by 5.4% (from
25.2% to 30.6%) in the group of patients who had
been assigned
to metformin and by 3.3% (from 33.4% to 36.7%)
in the placebo group.
Nine of 48 patients (19%) in the metformin group
and 3 of 30 patients (10%) in the placebo group
had not taken their coded medication for more
than 90
days before their washout glucose tolerance test,
the report indicates.
When both the study and the washout period were
combined, the odds of diabetes were still reduced
by 25% in
the metformin group compared with the placebo
group (p = 0.005), the researchers note, demonstrating "that
a transient pharmacological effect did not explain
the overall difference between metformin and placebo."
"
It appears that approximately one quarter of the
beneficial effect of metformin to prevent type 2
diabetes in the DPP was attributable to a pharmacological
effect that did not persist when the drug was withdrawn," the
authors conclude. "However, the overall effect
of metformin in preventing diabetes remained a substantial
25% after withdrawal, concordant with the conclusion
of the DPP that metformin reduces the conversion
to diabetes in individuals with impaired glucose
tolerance."
"
How long the effects of metformin on the underlying
pathophysiology of diabetes might last is unknown,
since the washout period rarely exceeded 14 days," the
investigators add.
Diabetes Care 2003;26:977-980.
================================
FACT: The
Diabetes Prevention Program found that diet and
exercise resulting in a 5- to 7-percent
weight loss lowered the incidence of type 2 diabetes
by 58 percent. Participants lost weight by cutting
fat and calories in their diet and by exercising
(most chose walking) at least 30 minutes a day,
5 days a week.
See the results of the 10,000 Step Study
