How Often Should People with Diabetes Check Their A1C?

Patient Expert

A new study concludes that people who have diabetes should check their blood glucose level with A1C tests more often than the experts recommend. But even then, the study doesn't go far enough.

The study looked at more than 400,000 tests by about 80,000 people whose doctors prescribed them between 2008 and 2011. It focused on the relationship between the retest interval and the percentage change in A1C level.

The results of this massive analysis just appeared in the current issue of Diabetes Care.  The abstract of the study  is free online, and an endocrinologist friend of mine kindly gave me a copy of the full text.

If you want to quickly reduce your A1C level, the best strategy is to get an A1C test every three months. That's the main conclusion of the study. This is particularly true if you level is 7.0 or more.

While Diabetes Care is a professional journal of the American Diabetes Association, this is more frequent than the ADA currently recommends. People who are "meeting their treatment goals" and who have stable blood glucose control should get their A1C tested at least every six months, according to the ADA's "Standards of Medical Care in Diabetes 2014." Only when people recently change their treatment or aren't achieving their blood sugar targets do they need to be tested every three months, the ADA's recommendation continues.

But what does "meeting their treatment goals" mean? While the ADA says that the goal can vary for different people, the general glycemic goal is an A1C level of less than 7.0.

This goal is just a little less than the average A1C level of Americans with diabetes in the most recent years for which data are available.  An analysis by the U.S. Centers for Disease Control and Prevention  found that the mean (average) A1C among adults with diagnosed diabetes in 1999 to 2006 was 7.2.

A conclusion that the typical American with diabetes needs to check his or her A1C level every three months is unavoidable. But the new study says that "testing more frequently than 2 months has no benefit over testing every 2-4 months."

Really? That's not what the above chart indicates. Testing frequency of people who have A1C levels above 7.0 has a U-shaped curve that rises only with testing every 3-4 months. But testing as frequently as every month works better for one group of people with diabetes: those of us who have an A1C level of less than 6.0.

The trend is basically upward from testing every month. This is a relatively small group, which is clear when we keep in mind that the average level is 7.2. This is also the group that will have fewer complications from diabetes, as the Diabetes Control and Complications Trial (DCCT) and United Kingdom Prospective Diabetes Study (UKPDS) established that there is a direct relationship between A1C levels and outcome risks in patients with diabetes.

So if you want to be as healthy as possible, the thing to do is to test your A1C level every month. That's what I have been doing for years, even though my level has come down to the low 5s. This gives me the information I need to eat less and exercise more.

If you check your blood sugar, you can manage it. If you don't check, you won't know what direction you are taking.