Silaja Cheruvu, R3

What’s the BEST way to prevent diabetes in high risk patients?

By doing nothing? With lifestyle changes? With medication?

27 centers 1996-1999 3234 participants “High Risk”

◦ 25 years old◦ BMI>24◦ Elevated fasting glucose, 2 hour GTT

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

Placebo arm◦ 77%

Metformin arm◦ 72%

Intensive Lifestyle Modification arm◦ 50% reached goal weight loss◦ 38% kept the weight off◦ 74% were exercising at 24 weeks◦ 58% kept exercising

Crude Incidence (person-years)◦ Placebo: 11◦ Metformin: 7.8◦ ILM: 4.8

Cumulative Incidence (over 3 years)◦ Placebo: 28.9 %◦ Metformin: 21.7 %◦ ILM: 14.4 %

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)

Were the patients randomized? Was randomization concealed? Were patients similar in prognostic factors?

◦ Table 1 Was the study blinded? How complete was the follow-up? Was the study stopped early? Intention to treat?

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.

Relative Risk Reduction◦ 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.

Number Needed to Treat (ILM)◦ NNT=1/ ARR◦ 1/0.145 = 7

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.

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.

UNM, Shiprock and Zuni◦ DIPS in Zuni

No subgroup analysis of high HbA1Cs vs low HBA1Cs

Subgroup analysis◦ Metformin arm NOT statistically significant in

Hispanics and Native Americans

Good study BUT it’s a surrogate outcome

Only followed for 3 years…◦ Blinded arm terminated early

Even with LOW adherence, ILM works!◦ …but so does metformin!

POLICY CHANGE◦ Can our patients exercise and do they access to

healthy foods?