Transcript Slide 1

Silaja Cheruvu, R3
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What’s the BEST way to prevent diabetes in
high risk patients?
 By doing nothing?
 With lifestyle changes?
 With medication?
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27 centers
1996-1999
3234 participants
“High Risk”
◦ 25 years old
◦ BMI>24
◦ Elevated fasting glucose, 2 hour GTT
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Placebo arm=Standard lifestyle
recommendations
Metformin arm
Troglitazone arm (discontinued early)
Intensive Lifestyle Modification arm
◦ Achieve/maintain a 7% weight loss
◦ 150 minutes/week
◦ 16 week curriculum
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Placebo arm
◦ 77%
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Metformin arm
◦ 72%
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Intensive Lifestyle Modification arm
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50%
38%
74%
58%
reached goal weight loss
kept the weight off
were exercising at 24 weeks
kept exercising
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Crude Incidence (person-years)
◦ Placebo: 11
◦ Metformin: 7.8
◦ ILM: 4.8
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Cumulative Incidence (over 3 years)
◦ Placebo: 28.9 %
◦ Metformin: 21.7 %
◦ ILM: 14.4 %
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Incidence of DM was REDUCED by 31% (CI:
17-43) in metformin arm
Incidence of DM was REDUCED by 58% (CI:
48-66) in ILM arm
NNT
◦ Metformin: 13.9 (CI: 8.7-33.9)
◦ ILM: 6.9 (CI: 5.4-9.5)
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Were the patients randomized?
Was randomization concealed?
Were patients similar in prognostic factors?
◦ Table 1
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Was the study blinded?
How complete was the follow-up?
Was the study stopped early?
Intention to treat?
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Absolute Risk Reduction
◦ ARR = CER – EER
◦ CER = 28.9%
◦ EER = 14.4%
 ARR = 28.9% - 14.4% = 14.5%
In those patients who are high risk for developing DM,
when followed for 3 years, 14.3% fewer develop DM if
they participate in ILM compared to placebo.
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Relative Risk Reduction
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RRR = (CER – EER ) /CER x 100
CER= 28.9
EER=14.4
(28.9% - 14.4%) / 28.9 % x 100 = 50%
Over a 3 year period, there is a 50% decrease in the incidence of
DM in ILM group when compared to the placebo group.
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Number Needed to Treat (ILM)
◦ NNT=1/ ARR
◦ 1/0.145 = 7
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Number Needed to Treat (metformin)
◦ NNT=1/ARR
◦ 1/0.072 = 14
In order to prevent 1 case of DM over a 3 year period, you
would have to treat 7 people with the intensive lifestyle
modifications and 14 people with metformin.
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Confidence Intervals and Precision
◦ Number Needed to Treat
 ILM: NNT=7 (CI: 5.4 to 9.5)
 Metformin: NNT=14 (CI: 8.7 to 33.9)
ILM arm is more precise than metformin arm but
both are statistically significant.
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UNM, Shiprock and Zuni
◦ DIPS in Zuni
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No subgroup analysis of high HbA1Cs vs low
HBA1Cs
Subgroup analysis
◦ Metformin arm NOT statistically significant in
Hispanics and Native Americans
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Good study BUT it’s a surrogate outcome
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Only followed for 3 years…
◦ Blinded arm terminated early
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Even with LOW adherence, ILM works!
◦ …but so does metformin!
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POLICY CHANGE
◦ Can our patients exercise and do they access to
healthy foods?