Diabetes Dateline
Spring 2010
A Decade Later, Both Lifestyle Changes
and Metformin Still Lower Type 2
Diabetes Risk
Study Reports on Persistence
of Benefits Seen in the
Diabetes Prevention Program
In 2002, the landmark randomized clinical
trial, the Diabetes Prevention Program (DPP),
reported outcomes 1 year early because of
significant, positive study results. This study
involved 3,234 adults at high risk for developing
type 2 diabetes who were randomized to three
treatment groups. The intensive lifestyle change
group aimed at modest weight loss reduced the
rate of developing type 2 diabetes over 3 years
by 58 percent compared with the control group.
Subsequently, DPP researchers provided support
for lifestyle change to all participants in the DPP
and followed participants to determine whether
the benefit of intensive lifestyle intervention persisted
over time. Now, after following the participants
for a total of 10 years after enrollment in the
DPP, the Diabetes Prevention Program Outcomes
Study (DPPOS) found that the early intensive
lifestyle intervention reduced the rate of developing
type 2 diabetes by 34 percent over 10 years.
The results appeared online October 29, 2009, in
The Lancet.
In addition to the intensive lifestyle change
group, DPP participants were also randomly
assigned to receive treatment with the oral diabetes
drug metformin. This group had a 31 percent
reduced rate of diabetes in the DPP. Continued
medication was offered to this group in the
DPPOS, and the researchers found an 18 percent
reduced rate of developing diabetes after 10 years,
compared with placebo.
Participants in the DPP who were randomly
assigned to make lifestyle changes also had more
favorable cardiovascular risk factors, including
lower blood pressure and triglyceride levels,
despite taking fewer drugs to control their heart
disease risk.
“In 10 years, participants in the lifestyle change
group delayed type 2 diabetes by about 4 years
compared with placebo, and those in the metformin
group delayed it by 2 years. The benefits
of intensive lifestyle change were especially pronounced
in the elderly. People age 60 and older
lowered their rate of developing type 2 diabetes
in the next 10 years by about half,” said David M.
Nathan, M.D., director of the Diabetes Center
at Massachusetts General Hospital and DPP/DPPOS chair.
At-risk
In the United States, about 11 percent of
adults—24 million people—have diabetes, and
up to 95 percent of these adults have type 2. An
additional 57 million adults, based on a 2007
estimate, have glucose levels that are higher
than normal but not yet in the diabetic range, a
condition called pre-diabetes, which substantially
raises the risk of a heart attack or stroke and of
developing type 2 diabetes in the next 10 years.
“The spiraling epidemics of obesity and type 2
diabetes in the United States and worldwide
show no signs of abating,” said Griffin P.
Rodgers, M.D., M.A.C.P., director of the
National Institute of Diabetes and Digestive
and Kidney Diseases (NIDDK). “Millions of
people could delay diabetes for years and possibly
prevent the disease altogether if they lost
a modest amount of weight through diet and
increased physical activity.”
Striking as the DPP findings were, the researchers
did not know how long the benefit would
endure, because DPP results were based on
just 3 years of data. During a bridge period
from January to July 2002, all participants were
told the study’s results and were offered the
16-session intensive lifestyle change program.
The metformin group was also offered continued
metformin therapy in the DPPOS. The majority
of the DPP volunteers—88 percent—chose to
participate in the DPPOS.
Intensive Lifestyle Changes
In the DPP trial, the intensive lifestyle change
included lowering fat and calorie intake and
increasing regular physical activity up to 150
minutes per week. Participants in this lifestyle
intervention group received training in diet, exercise,
and behavior modification. In the DPP’s
first year, this group lost 15 pounds on average,
but those followed in the DPPOS regained all
but about 5 pounds from their starting weight
over 10 years. The metformin group lost about
5 pounds during the DPP study, and this loss in
weight was maintained in those followed in the
DPPOS. The placebo control group lost less
than 2 pounds over the decade.
About 5 to 6 percent of those in the lifestyle
intervention group developed type 2 diabetes
annually, an incidence rate that remained steady
throughout the DPPOS. When the DPP ended
in 2001, the metformin and placebo groups
developed diabetes at the rate of 8 and 11 percent a year, respectively. However, 10 years after randomization
of the DPP participants, the yearly
diabetes incidence rates for those in the DPPOS
metformin and original DPP control groups also
fell to about 5 to 6 percent.
Researchers are looking at a number of explanations
for the convergence of diabetes incidence
rates for the three DPP groups. One possibility
is that lifestyle change adopted by the metformin
and placebo groups after the DPP ended lowered
their rate of type 2 diabetes over time.
The DPP and the DPPOS have been funded
by the NIDDK and other National Institutes of
Health Institutes and Centers, with additional
funding from the Indian Health Service, the
Centers for Disease Control and Prevention, the
American Diabetes Association, and the private
sector.
The NIDDK offers free easy-to-read booklets
and fact sheets about diabetes, including a fact
sheet about the DPP. For more information or to
obtain copies, visit www.diabetes.niddk.nih.gov.
NIH Publication No. 10–4562
April 2010
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