Should Diabetes Treatment Be Changed

by Nancy Keating, M.D., M.P.H.

Q. I've had type 2 diabetes for 12 years; I'm now 81. I take metformin plus Januvia. My doctor has never suggested that I monitor myself on a daily basis with a meter. My hemoglobin A1c has been creeping up and is now at 7. Should I be getting more aggressive in my treatment?

A. You have type 2 diabetes, which used to be called adult-onset diabetes. This type of diabetes is caused mainly by insulin resistance. Normally, insulin helps usher blood sugar (which is the same thing as glucose) out of the bloodstream and into cells where it is used for energy. When people develop insulin resistance, cells turn away insulin, so the amount of sugar circulating in the blood goes up, and sugar-laden blood leads to numerous problems, including damage to the eyes, kidneys, and nerves and a higher risk of heart attacks and strokes.

You should congratulate yourself that after 12 years of having diabetes, your hemoglobin A1c level is still only 7. The hemoglobin A1c test measures the amount of sugar "stuck" to hemoglobin, a protein in red blood cells, and it reflects blood sugar levels over the previous several months. For most people with diabetes, the goal is to keep the hemoglobin A1c level at or below 7, which represents fairly tight control of blood sugar levels. Tight control can lead to dangerously low blood sugar (hypoglycemia) in older people, causing confusion, light-headedness, and fainting, so a hemoglobin A1c level of 8 or less can be a reasonable goal.

It makes sense that you are taking metformin (Glucophage). It's the first-line drug for type 2 diabetes, and most people with the disease need medication to keep blood sugar levels under control. Metformin has several advantages over other medications. It lowers blood sugar levels, but it poses little danger of lowering them too far so people become hypoglycemic. Unlike some diabetes drugs, it doesn't cause weight gain. And it's an older drug, so it has a track record and is available as a relatively inexpensive generic.

Unfortunately, most patients eventually require additional medications to keep their blood sugar levels down and therefore their hemoglobin A1c measurements in a good range. In one large study, among patients whose blood sugar levels were originally controlled with a single drug, half required the addition of a second drug after three years, and three-quarters required multiple drugs or the addition of insulin to achieve the target level after nine years.

You're already taking a second drug, sitagliptin (Januvia), which is also available in a combination pill with metformin called Janumet. Sitagliptin was approved by the U.S. Food and Drug Administration in 2006, so it's relatively new, and it's the only drug in its class -- called DPP-4 inhibitors -- on the market in the United States.

You're doing well, but most people with diabetes taking oral medications eventually need to go on insulin, which must be injected. You may have already been treated with a sulfonylurea, another class of drugs that have been used for a long time; if you haven't, and your hemoglobin A1c level goes up, you may want to try a sulfonylurea before starting in with insulin injections.

As for monitoring your blood sugar, there's uncertainty about that. For patients who need insulin, blood glucose monitoring can be helpful, but it may not be necessary for those taking oral medications. A study published in the British journal BMJ found that among patients taking oral medications for their diabetes, self-monitoring of blood sugar levels did not improve control of hemoglobin A1c.

Given the lack of benefit, and the discomfort associated with pricking one's finger regularly to get blood for testing, I don't usually recommend self-monitoring for my patients on oral medications. Still, some doctors recommend it if they think that it will motivate their patients with diabetes to eat better and exercise more.

I think it comes down to this: If your hemoglobin A1c level continues to rise, you will need to get more aggressive in your treatment, which may eventually include insulin injections. Monitoring your blood glucose now isn't essential, but it may be helpful if you do begin taking insulin. Work on your diet and physical activity level. Progress there may help put off the need for insulin.

It is also important to keep your blood pressure and cholesterol levels controlled because that will lower your risk of heart disease. Studies suggest that controlling blood sugar may be more important for lowering your risk of microvascular damage to the eyes, kidneys, and nerves than it is for lowering your heart attack and stroke risk.

Nancy Keating, M.D., M.P.H., Brigham and Women's Hospital, Boston, Massachusetts

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