The Cost-Effectiveness of Strategies To Prevent Type 2 Diabetes

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The summary below is from the full report titled "The Cost-Effectiveness of Lifestyle Modification or Metformin in Preventing Type 2 Diabetes in Adults with Impaired Glucose Tolerance." It is in the 1 March 2005 issue of Annals of Internal Medicine (volume 142, pages 323-332). The authors are W.H. Herman, T.J. Hoerger, M. Brandle, K. Hicks, S. Sorensen, P. Zhang, R.F. Hamman, R.T. Ackermann, M.M. Engelgau, and R.E. Ratner, for the Diabetes Prevention Program Research Group.

What is the problem and what is known about it so far?

Type 2 diabetes (adult-onset diabetes) interferes with the body's ability to store energy from food. The result is high levels of blood sugar. Over time, high blood sugar levels lead to complications, such as blindness, kidney failure, and heart disease. Many people with type 2 diabetes have moderately high levels of blood sugar for years before the levels reach true diabetes levels and symptoms begin. This condition is called abnormal glucose tolerance or prediabetes. A large study showed that 2 different methods can prevent or delay the development of diabetes in people with prediabetes. The first method is an intensive diet and exercise program for weight loss. The other is a small daily dosage of a diabetes medication called metformin. Because many Americans have prediabetes, using 1 of these prevention methods in all people who might benefit would be expensive. However, caring for diabetes and its complications is also expensive. It is important to know whether the costs of diabetes prevention are worth the potential benefits.

Why did the researchers do this particular study?

To estimate whether the costs of using a diet and exercise program or metformin to prevent type 2 diabetes is worth the potential benefits.

Who was studied?

Rather than studying actual patients, the researchers used computers to simulate what would happen to a virtual group of adults with prediabetes if they did or did not use a diet and exercise program or metformin to prevent diabetes.

How was the study done?

The researchers used published information to estimate what might happen (and how much it would cost) if doctors prescribed either intensive diet and exercise counseling or metformin for adults with prediabetes. They also estimated what might happen (and how much it would cost) if doctors did nothing to prevent diabetes in these patients. They put these estimates into the computer model and calculated how much each strategy would cost per year of life that is saved.

What did the researchers find?

The researchers estimated that diet and exercise or metformin would delay diabetes, reduce complications, and improve survival. The effect of diet and exercise was more favorable than the effect of metformin. Compared with no prevention, diet and exercise counseling cost about $8800 and metformin would cost about $29,000 per quality-adjusted life-year saved. While diet and exercise had favorable cost-effectiveness profile at any adult age, metformin was not cost-effective after age 65 years.

What were the limitations of the study?

The study was a computer simulation, so we cannot be sure what the results would be with actual patients.

What are the implications of the study?

These levels of cost–benefit were well within the range that U.S. society is typically willing to pay for health care treatments. Policymakers should promote diet and exercise programs for adults with prediabetes, with metformin as a reasonable but less economically attractive alternative.