Researchers Hope to Better Define Prediabetes

Mary R. Rooney, PhD, MPH

A better definition of prediabetes could yield a better way to forecast which patients might be at a higher risk of developing diabetes.

A team, led by Mary R. Rooney, PhD, MPH, Welch Center for Prevention, Epidemiology, and Clinical Research, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, compared different definitions and characterized the risks of prediabetes and diabetes among older adults in a community-based setting.

“The construct of prediabetes is used to identify those individuals at high risk for developing diabetes in the future,” the authors wrote. “In this older population, few individuals who met the definitions of prediabetes progressed to diabetes.”

Diabetes Risk

In the prospective cohort study, the investigators examined 3412 older adults without diabetes from the Atherosclerosis Risk in Communities Study. The mean age of the patient population was 75.6 years old and 60% of the participants were female.

Each individuals was contacted semi-annually between baseline—2011-2013—and 2017. They also attended a follow-up visit between 2016-2017 (median [range] follow-up, 5.0 years).

A total of 2497 participants between 45-64 years old at baseline attended the follow-up visits or died. The study organizers excluded all patients with a history of diagnosed diabetes and participants with HbA_1c levels of 6.5% or higher.

The investigators sought main outcomes of incident total diabetes—physician diagnosis, glucose-lowering medication use, HbA_1c level 6.5%, or FG level 126 mg/dL.

There were 156 incident total diabetes cases (118 diagnosed) and 434 deaths during the 6.5 year follow-up period.

In addition, there were a total of 1490 participants (44%) had HbA1c levels of 5.7-6.4%, 1996 (59%) had IFG, 2482 (73%) met the HbA_1c or IFG criteria, and 1004 (29%) met both the HbA_1c and IFG criteria.

For the patients with HbA_1c levels of 5.7-6.4% at baseline, 97 (9%) progressed to diabetes, 148 (13%) regressed to normoglycemia (HbA_1c, <5.7%), and 207 (19%) died.

For the individuals with IFG at baseline, 112 (8%) progressed to diabetes, 647 (44%) regressed to normoglycemia (FG, <100 mg/dL), and 236 (16%) died.

Of those with baseline HbA_1c levels less than 5.7%, 239 (17%) progressed to HbA1c levels of 5.7% to 6.4% and 41 (3%) developed diabetes, while of those with baseline IFG levels less than 100 mg/dL, 80 (8%) progressed to IFG (FG, 100-125 mg/dL) and 26 (3%) developed diabetes.

Prediabetes

“In this community-based cohort study of older adults, the prevalence of prediabetes was high; however, during the study period, regression to normoglycemia or death was more frequent than progression to diabetes,” the authors wrote. “These findings suggest that prediabetes may not be a robust diagnostic entity in older age.”

Past research has indicated that the prevalence of prediabetes and diabetes increases substantially with age, with an estimated 25% of adults 65 or older having diabetes in the US and 50% of these patients meeting the criteria for prediabetes depending on the definition used.

The American Diabetes Association has indicated hyperglycemia can help forecast these conditions in older adults.

The study, “Risk of Progression to Diabetes Among Older Adults With Prediabetes,” was published online in JAMA Internal Medicine.