Harvard Heart Letter

Ask the doctors: Should I worry about prediabetes?

Q. I have coronary artery disease, and my primary care doctor just told me that changes in my tests indicate I have prediabetes. This doesn't sound like a big deal, since I don't need medicines yet. But I'm wondering if I should start doing anything differently?

A. You raise an important issue relevant to millions of Americans, because type 2 diabetes damages blood vessels. In fact, this prediabetes phase is an absolutely critical time for you, especially because you have coronary artery disease. Almost everyone who gets type 2 diabetes passes through a prediabetes phase, when their glucose tests show modest, but worrisome, elevations, but their blood sugar readings aren't high enough to need oral diabetes drugs or insulin.

Insulin produced by the pancreas normally drives sugar from the blood into the cells, where it is needed for energy. In type 2 diabetes, the body becomes resistant to insulin, which causes blood sugar levels to rise. At first, the pancreas responds by making more insulin than normal. However, after many years of doing this, the insulin-producing cells become exhausted. At that point, blood sugar rises higher, and you have diabetes.

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