How Often Does Prediabetes Become Diabetes?

Text Size:
How Often Does Prediabetes Become Diabetes?

The concept of “prediabetes”  —a condition defined as a blood sugar level that’s high but not high enough to be considered diabetes — was established some 25 years ago, but the idea has remained vague. Prediabetes is defined by HbA1c (A1C), which measures a person’s blood sugar level over the preceding two or three months, but just what HbA1c level indicates prediabetes hasn’t been fixed, and how many people who have prediabetes go on to develop diabetes is uncertain. That’s been a challenge, because good statistics would help experts understand the scope of the problem. In a new study on prediabetes just published in a JAMA Network Open research letter, the authors explained, “Data on progression to diabetes in older adults are essential to guide policy because lifestyle intervention programs may not be cost-effective when progression rates are low. Existing data are limited and show a wide range of progression rates. Although recommendations for using hemoglobin A1c (HbA1c) to diagnose prediabetes are common, the progression rate of HbA1c-defined prediabetes in clinical settings among older US adults remains unclear.”

To get cutting-edge diabetes news, strategies for blood glucose management, nutrition tips, healthy recipes, and more delivered straight to your inbox, sign up for our free newsletters!

The research team retrieved their data from what’s known as the Longitudinal Epidemiologic Assessment of Diabetes Risk (LEADR) study. An initiative created by the U.S. Centers for Disease Control (CDC), the LEADR database contains almost 568 million data records used to determine the risk of developing diabetes. The database includes such factors as medical history, demographics, and lifestyle changes. The research team identified 50,152 people who had been diagnosed with prediabetes (defined as an HbA1c level from 5.7-6.4%). They ranged in age from 65 to over 80, about 60% were male, and some three-fourths were white, while Black patients made up 10% and Hispanic 11%. Body-mass indexes (BMIs, a measure of weight relative to height) of the subjects ranged from below 18.5 to over 40 (above 30 is considered obese), and more than half of the subjects (60%) had been diagnosed with hypertension (high blood pressure). The average follow-up was 2.3 years, and the researchers determined the incidence of diabetes by using the annual progression rate (APR) of diagnosed cases.

Rate, factors for prediabetes to diabetes progression identified

In all, the researchers found the estimated APR to diabetes among older adults with prediabetes was 5.3%, which meant that about one in 20 U.S. adults 65 or above with prediabetes develop diabetes within the following year. The most principal factors in determining whether a person progresses to diabetes were BMI and baseline HbA1c. For example, people with a BMI above 40 had an APR of 7.6% and the percentages went down as BMIs went down. People with a BMI of 35 had an APR of 7.3; a BMI of 30 was 6.4, and so on, until those with a BMI below 18.5 had an APR of 3.9%. When it came to HbA1c levels, people in the lower range (5.7-5.9%) had an APR of 2.8%, while for people in the higher range (6.0-6.4%) it was 8.2% — a dramatic difference. It was no surprise to find APR rates were higher in people with a family history of diabetes and in people who had been diagnosed with hypertension, but it was a bit unexpected to find categories in which differences were slight or nonexistent. For example, age didn’t seem to be much of a factor and neither was race.

The authors of the new study cautioned that their data was “representative of patients comprising the health care organizations contributing data and may not be representative of the general U.S. population.” Nevertheless, they hoped their work might shed light on the debate among diabetes specialists on how seriously to take an evaluation of prediabetes and what to do about it. As they put it, “Our findings may provide important information to evaluate the cost-effectiveness of lifestyle interventions in older adults with prediabetes.” At the very least, the results underlined the importance of controlling BMI and HbA1c.

Want to learn more about prediabetes? Read “What Is Prediabetes? Symptoms, Treatment, and More,” “Prediabetes Treatment” and “Diabetes Prevention: Eat to Beat Diabetes.”

Joseph Gustaitis

Joseph Gustaitis

Joseph Gustaitis on social media

A freelance writer and editor based in the Chicago area, Gustaitis has a degree in journalism from Columbia University. He has decades of experience writing about diabetes and related health conditions and interviewing healthcare experts.

Save Your Favorites

Save This Article