A doctor is talking to a patient
Borderline diabetes is a condition that develops before an individual gets type 2 diabetes.

Borderline Diabetes

As a diabetes educator, I’ve heard many patients say that they have “borderline diabetes.”

Ahhh. “Borderline diabetes.” What exactly is “borderline diabetes?” Does this mean that you have diabetes? You kind of have diabetes? Or you are on the fence of having diabetes?

As it turns out, “borderline diabetes” isn’t a medical termWhen someone tells me they have “borderline diabetes” it could mean any of these things, depending on what their physician thinks “borderline diabetes” is.

Confusing, right?

What Is Borderline Diabetes?

Most people agree that “borderline diabetes” is synonymous with prediabetes – another type of diabetes. Prediabetes can be defined as blood sugar levels that are higher than normal, but not high enough to be diagnosed as type 2 diabetes.


People who have prediabetes are at an increased risk for developing not just type 2 diabetes, but also cardiovascular diseases such as coronary artery disease, heart attack, and stroke.

The incidence of prediabetes is staggering – an estimated 84.1 million adults in the U.S. have prediabetes. This is an estimated 33.9 percent of U.S. adults. When we break this down by age, 23.1 million adults over the age of 65 have prediabetes (48.3 percent). Comparing men to women, men are more likely to have prediabetes than women – 36.6 percent versus 29.3 percent.

Borderline Diabetes Symptoms

Borderline diabetes typically has no symptoms, which is similar to diabetes. Why? Diabetes is often thought of as a “silent disease” – elevated blood sugar typically does not manifest symptoms until blood sugar levels are dangerously high.

As such, borderline line diabetes likely will not cause symptoms until it has progressed to type 2 diabetes. Symptoms may develop if another complication develops, such as a heart attack or stroke. These symptoms would be related to the complication, and borderline diabetes would then likely be diagnosed after the complication.

Borderline Diabetes Risk Factors

There are several risk factors for the developing of borderline diabetes. You may have just one risk factor, or you may have several.

  • Genetics increases the risk of developing borderline diabetes.
  • Weight can play a role. Being either overweight or obese can both increase the chance of having borderline diabetes, as fat is known to reduce insulin sensitivity, making cells insulin resistant.
  • Having a large waist increases the risk. This typically means that you are carrying excess fat, and as we discussed above, this reduces insulin sensitivity.  A woman with a waist over 35 inches or a man with a waist over 40 inches is at an increased risk.
  • Being age 45 or older. This could be due to a poor diet, reduced activity, and a loss of muscle mass.
  • Sleep patterns those with obstructive sleep apnea appear to have an increased risk of sleep apnea.
  • Stress causes a release of cortisol, which may cause blood sugar levels to rise.
  • Gestational diabetes having a personal history of gestational diabetes are at a higher risk of both prediabetes and type 2 diabetes.
  • Women with polycystic ovarian syndrome (PCOS) are more likely to be insulin resistant, which can lead to both prediabetes and type 2 diabetes. However, women with type 1 diabetes are also more likely to develop PCOS.

Borderline Diabetes Diagnosis

Borderline diabetes can only be diagnosed by a blood test. There are several blood tests that can be used to screen for borderline diabetes. These include an A1c test, a random blood sugar, or a glucose tolerance test.

According to the World Health Organization, the A1c is considered the most reliable way to diagnose prediabetes and diabetes. However, the A1c test is not available in all countries. It is also not reliable for people with certain conditions, such as anemia, malaria, who have had recent blood loss or a recent blood transfusion, who are pregnant, or even who are smokers.

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An A1c level does not require the person to fast prior to the test. This test measures an average blood sugar level for past two to three months. This average is equated to a percentage – a percentage of 5.7 percent to 6.4 percent indicates prediabetes. An A1c of greater than 6.4 percent is diagnostic for diabetes.

A fasting blood sugar level of 100 to 125 mg/dL indicates prediabetes. A random blood sugar level of 140 to 199 mg/dL also indicates prediabetes. If a blood draw reveals an elevated level, a second draw on another day is required to confirm a diagnosis.

Screening for prediabetes should occur for all individuals over the age of 45 who are overweight if they have any of they have any of the risk factors listed below:

  • Hypertension.
  • History of gestational diabetes.
  • Previously given birth to a baby weighing more than nine pounds.
  • Physical inactivity.
  • A first-degree relative with diabetes.
  • Signs of insulin resistance.
  • High cholesterol levels.
  • An ethnic background of African-American, Pacific Islander, Asian-American, Native American, Latino, or Hispanic-American.

Borderline Diabetes Treatment

In general, treatment is aimed at healthy lifestyle choices. Making changes could reduce blood sugar levels, thus prevent prediabetes from progressing to type 2 diabetes.

Mayo Clinic recommends the following:

  • Eat a healthy diet. This includes choosing foods that are high in fiber and low in fat.  For example, choose fruits, vegetables, and whole grains.  Eating a variety of foods from these food groups can improve blood sugar levels.
  • Stop/Quit smoking. It’s no secret that smoking is bad for everyone’s health – but it is really bad for someone who has elevated blood sugar levels.
  • Increase activity. Getting active can reduce blood sugar levels.  Shoot for 30 to 60 minutes of activity on most days of the week.
  • Lose weight. Losing even 5 to 10 percent of your weight can reduce the risk of prediabetes from progressing to type 2 diabetes.

You may have heard of a medication called metformin and are wondering why your physician is asking you to take this drug. After all, your friend with diabetes is taking it – why do you have a prescription for it when you only have prediabetes?

Metformin is absolutely the initial drug of choice for type 2 diabetes. It is now considered a treatment choice for people with prediabetes if their physician believes that they are at a high risk of developing type 2 diabetes. According to the American Medical Association, it should especially be considered “in those who are <60 years old, have a BMI >35 kg/m2, or have a history of gestational diabetes.”

The Diabetic Prevention Program (DPP) trial evaluated over 3000 nondiabetic patients. These patients had elevated fasting glucose levels and received intensive lifestyle intervention, metformin 850mg twice daily, or a placebo. At the conclusion of the trial, which was approximately three years, those patients who received intensive lifestyle intervention or metformin had approximately the same outcome – a reduced incidence of diabetes.

Can Borderline Diabetes Be Reversed?

Some experts believe that prediabetes can be reversed.

Marvin M. Lipman, an endocrinologist, states, “pre-diabetes is absolutely reversible.”

That being said, experts who believe that prediabetes is reversible also believe that it is reversible with work. Remember when we discussed the tips from Mayo Clinic – losing weight, improving diet, getting exercise, smoking cessation? Doing these things could be the ticket to reversing prediabetes.


Dr. Lipman also points out that losing weight is important. Carrying excess fat increases insulin resistance.  Therefore, losing weight improves insulin sensitivity. This allows the body to use its own hormone – insulin – more effectively, therefore reducing blood sugar levels.

The Bottom Line…

Typically, “borderline diabetes” means “prediabetes.” However, if your physician tells you that you have borderline diabetes, ask for clarification – what exactly is your A1c or glucose level? How should you treat it?

And remember – you can prevent type 2 diabetes with the proper treatment.