Prediabetes and A1c: how to turn the numbers around

Prediabetes rarely causes symptoms, so most people learn about it from a blood test. The good news is that it is one of the clearest examples in medicine of a problem you can often reverse, and the evidence is especially encouraging for people over 60.

What the A1c test measures

The A1c test, sometimes written HbA1c, reflects your average blood sugar over roughly the past three months. It does not require fasting, which is one reason it is widely used. The National Institute of Diabetes and Digestive and Kidney Diseases gives these ranges:

• Normal: below 5.7 percent
• Prediabetes: 5.7 to 6.4 percent
• Diabetes: 6.5 percent or above, usually confirmed with a second test

Fasting glucose and a glucose tolerance test are other ways to make the diagnosis. NIDDK notes that some conditions, including iron-deficiency anemia, kidney failure and liver disease, can make an A1c result inaccurate, which is one reason your doctor reads it alongside your other labs.

How common it is, and who should be screened

The CDC estimates that more than 2 in 5 American adults have prediabetes. Prediabetes raises the risk of type 2 diabetes and other health problems. NIDDK explains that it is closely tied to insulin resistance, in which the body’s cells do not respond well to insulin.

The US Preventive Services Task Force recommends screening adults aged 35 to 70 who have overweight or obesity, and offering people with prediabetes effective prevention programs. Medicare covers diabetes screening tests for people with certain risk factors.

NIDDK notes that people with insulin resistance and prediabetes usually have no symptoms. The same page lists factors that raise the chance of developing it:

• Overweight, obesity or a large waist size
• Age 35 or older, with risk rising as people get older
• A family history of diabetes
• Not being physically active
• Smoking, including e-cigarettes
• A history of diabetes during pregnancy

Because nothing feels wrong, the only way to know is a blood test. That is one reason an A1c is part of many annual physicals for adults with these risk factors.

The evidence that it can be turned around

The landmark Diabetes Prevention Program, published in the New England Journal of Medicine in 2002, randomly assigned adults at high risk to an intensive lifestyle program, metformin, or placebo. The lifestyle program reduced the development of diabetes by 58 percent over about three years, and worked better than metformin.

According to NIDDK, the lifestyle program worked particularly well for people 60 and older, lowering their chances of developing type 2 diabetes by 71 percent. The program’s goals were modest: losing about 7 percent of body weight and getting about 150 minutes of physical activity a week.

What helps most

• Modest weight loss. For many people, 5 to 7 percent of body weight is enough to move the numbers.
• Regular activity. Walking after meals, strength training and anything that gets you moving most days. See strength training after 50.
• A steady eating pattern. Fewer sugary drinks and refined starches, more vegetables, legumes, whole grains and fiber. A Mediterranean-style pattern is a good fit.
• Sleep. NHLBI links ongoing sleep deficiency to diabetes, among other conditions. See how sleep changes with age.
• A structured program, if you like support. The CDC-recognized National Diabetes Prevention Program is based on the original study, and the CDC says lifestyle change can cut the risk of type 2 diabetes in half.

Some people with prediabetes are also offered medicine. That decision depends on age, weight, other conditions and how the numbers are trending, and it is one to make with your doctor.

How progress is tracked

Because A1c reflects about three months of blood sugar, it is usually rechecked no sooner than that after a change in habits or treatment. Fasting glucose, weight, waist size and blood pressure fill in the picture between tests. Seeing the number move in the right direction is often the best motivation there is.

Why your internist cares about the whole picture

Prediabetes rarely travels alone. It often comes with high blood pressure, high triglycerides, fatty liver and early changes in kidney function. Because Dr. Shtern is also a nephrologist, she pays close attention to the kidney side; our article on eGFR, creatinine and UACR explains those tests. If weight is part of the plan, you may also want to read about GLP-1 medications, covered elsewhere in the journal.

At Legacy Medical, labs including an A1c are drawn in the office, and chronic disease care means the numbers are followed between visits, not just once a year. If you would like a doctor to keep track with you, book a complimentary meet and greet.

This article is general information, not advice for your situation. Members can call the office with questions about their own care.