The Cleveland Clinic

Diabetes: Pre-Diabetes

Introduction

Before people develop type 2 diabetes, they almost always have an asymptomatic condition called "pre-diabetes." Also known as "impaired glucose tolerance," pre-diabetes is a term that refers to the 41 million people in the U.S. who have blood glucose levels that are higher than normal, but are not high enough to be classified as diabetes.

More and more, doctors are recognizing the importance of diagnosing pre-diabetes as treatment of the condition may prevent type 2 diabetes as well as the complications associated with type 2 diabetes, such as heart and blood vessel disease and eye and kidney disease. Doctors now know that the complications associated with the condition occur before the diabetes diagnosis is made.

Who's At Risk For Developing Type 2 Diabetes?

  • People with a family history of type 2 diabetes
  • Women who had gestational diabetes or have had a baby more than 9 pounds
  • Women who have polycystic ovary syndrome (PCOS)
  • • African Americans, Native Americans, Latinos, and Pacific Islanders, minority groups that are disproportionately affected by diabetes
  • People who are overweight or obese especially around the abdomen
  • People with high cholesterol, high triglycerides, low good 'HDL' cholesterol and a high bad 'LDL' cholesterol and high blood pressure. This cluster of problems is known as the metabolic syndrome or insulin resistance.
  • People who are inactive
  • Older people. As people age they are less able to process glucose appropriately and therefore have a greater risk of developing type 2 diabetes.

Symptoms of pre-diabetes

Although most people with pre-diabetes have no symptoms at all, symptoms of diabetes may include unusual thirst, a frequent desire to urinate, blurred vision, or extreme fatigue.

A lab test may show some signs that suggest pre-diabetes may be present.

Who Should be Tested for Pre-Diabetes?

You should be tested if:

  • You're over 45 years of age
  • You have any risk factors for diabetes
  • You're overweight with a BMI (body mass index) over 25
  • You belong to a high risk ethnic group
  • You were know to previously have an abnormal glucose tolerance test (see below) or have an impaired fasting glucose level (see below)
  • You have a history of gestational diabetes or delivering a baby that weight more than 9 lbs
  • You have high triglycerides and low HDL cholesterol, central obesity and hypertension (the metabolic insulin resistance syndrome)

If your weight is normal and you're over age 45, you should ask your doctor during a routine office visit if testing is appropriate.

How Is Pre-Diabetes Diagnosed?

Your doctor can perform two different blood tests - the fasting plasma glucose (FPG) test and the oral glucose tolerance test (OGTT) -- to determine if you have pre-diabetes.

During the FPG test your blood glucose level is measured after an 8 hour fast. This test can determine if your body metabolizes glucose correctly. If your blood glucose level is abnormal after the fasting plasma glucose (FPG) test, you could have what's called "impaired fasting glucose," which suggests pre-diabetes.

Understanding the FPG Test Results

Condition FPG
Normal Less than 100 mg/dL (milligrams per deciliter)
Pre-diabetes 100 mg/dL - 125 mg/dL
Diabetes Greater than 126 mg/dL on two or more tests

The other test your doctor can perform is the oral glucose tolerance test. During this test, your blood sugar is measured after a fast and then again 2 hours after drinking a beverage containing a large amount of glucose. Two hours after the drink, if your glucose is higher than normal, you have what's called "impaired glucose tolerance," which suggests pre-diabetes.




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