Rethinking A1c goals for type 2 diabetes
“Treat the patient, not the number.” This is a very old and sound medical school teaching. However, when it comes to blood sugar control in diabetes, we have tended to treat the number, thinking that a lower number would equal better health.
Uncontrolled type 2 diabetes (also known as adult-onset diabetes) is associated with all sorts of very bad things: infections, angry nerve endings causing chronic pain, damaged kidneys, vision loss and blindness, blocked arteries causing heart attacks, strokes, and amputations… So of course, it made good sense that the lower the blood sugar, the lower the chances of bad things happening to our patients.
Tracking blood sugar control over time
One easy, accurate way for us to measure a person’s blood sugar over time is the hemoglobin A1c (HbA1c) level, which is basically the amount of sugar stuck to the hemoglobin molecules inside of our blood cells. These cells last for about three months, so, the A1c is thought of as a measure of blood sugars over the prior three months.
Generally, clinical guidelines have recommended an A1c goal of less than 7% for most people (not necessarily including the elderly or very ill), with a lower goal — closer to normal, or under 6.5% — for younger people.
We as doctors were supposed to first encourage diet and exercise, all that good lifestyle change stuff, which is very well studied and shown to decrease blood sugars significantly. But if patients didn’t meet those target A1c levels with diet and exercise alone, then per standard guidelines, the next step was to add medications, starting with pills. If the levels still weren’t at goal, then it was time to start insulin injections.
While all this sounds very orderly and clinically rational, in practice it hasn’t worked very well. I have seen firsthand how enthusiastic attention to the A1c can be helpful as well as harmful for patients.
And so have experts from the Clinical Guidelines Committee of the American College of Physicians, a well-established academic medical organization. They examined findings from four large diabetes studies that included almost 30,000 people, and made four very important (and welcome!) new guidelines around blood sugar control. Here’s the big picture.
Doctors and patients should discuss goals of treatment together and come up with an individual plan
Blood sugar goals should take into account a patient’s life expectancy and general health, as well as personal preferences, and include a frank discussion of the risks, benefits, and costs of medications. This is a big deal because it reflects a change in how we think about blood sugar control. It’s not a simply number to aim for; it’s a discussion. Diabetes medications have many potential side effects, including dangerously low blood sugar (hypoglycemia) and weight gain (insulin can cause substantial weight gain). Yes, uncontrolled blood sugars can lead to very bad things, but patients should get all the information they need to balance the risks and benefits of any blood sugar control plan.
An A1c goal of between 7% and 8% is reasonable and beneficial for most patients with type 2 diabetes…
…though if lifestyle changes can get that number lower, then go for it. For patients who want to live a long and healthy life and try to avoid the complications of diabetes, they will need to keep their blood sugars as normal as possible — that means an A1c under 6.5%. However, studies show that using medications to achieve that goal significantly increases the risk of harmful side effects like hypoglycemia and weight gain. To live longer and healthier and avoid both the complications of diabetes as well as the risks of medications, there’s this amazing thing called lifestyle change. This involves exercise, healthy diet, weight loss, and not smoking. It is very effective. Lifestyle change also can help achieve healthy blood pressure and cholesterol levels, which in turn reduce the risk for heart disease. And heart disease is a serious and common complication of diabetes.
Lifestyle change should be the cornerstone of treatment for type 2 diabetes. The recommendations go on to say that for patients who achieve an A1c below 6.5% with medications, we should decrease or even discontinue those drugs. Doing so requires careful monitoring to ensure that the person stays at the goal set with his or her doctor, which should be no lower than 7%, for the reasons stated above.
We don’t even need to follow the A1c for some patients
Elderly patients, and those with serious medical conditions, will benefit from simply controlling the symptoms they have from high blood sugars, like frequent urination and incontinence, rather than aiming for any particular A1c level. Who would be included in this group? People with a life expectancy of less than 10 years, or those who have advanced forms of dementia, emphysema, or cancer; or end-stage kidney, liver, or heart failure. There is little to no evidence for any meaningful benefit of intervening to achieve a target A1c in these populations; there is plenty of evidence for harm. In particular, diabetes medications can cause low blood sugars, leading to weakness, dizziness, and falls. There is the added consideration that elderly and sick patients often end up on a long list of medications that can (and do) interact, causing even more side effects.
The bottom line
There is no question that type 2 diabetes needs to be taken seriously and treated. But common sense should rule the day. Lifestyle changes are very effective, and the side effects of eating more healthfully and staying more active are positive ones. Every person with type 2 diabetes is an individual. No single goal is right for everyone, and each patient should have a say in how to manage their blood sugars and manage risk. That means an informed discussion, and thoughtful consideration to the number.
Hemoglobin A1c targets for glycemic control with pharmacologic therapy for nonpregnant adults with type 2 diabetes mellitus: A guidance statement update from the American College of Physicians. Annals of Internal Medicine, March 2018.
An overview of the management of diabetes in non-pregnant adults. MGH Primary Care Office Insite, updated June 2016.
Management of persistent hyperglycemia in type 2 diabetes mellitus. UpToDate, updated April 2017.