Study Estimates Risk of Progressing to Diabetes Among Older Diabetes with Prediabetes

An analysis from the Johns Hopkins Bloomberg School of Public Health is providing insight into the real-world risk of progression to diabetes among older patients with prediabetes.

Using data from the Atherosclerosis Risk in Communities (ARIC) study, investigators assessed risk of progression in more than 3000 patients and found regression to normoglycemia was more common than progression to diabetes during a nearly 7-year follow-up period.

"Our results suggest that for older adults with blood sugar levels in the prediabetes range, few will actually develop diabetes," said study senior author Elizabeth Selvin, PhD, professor in the Department of Epidemiology at the Bloomberg School. "The category of prediabetes doesn't seem to be helping us identify high-risk people. Doctors instead should focus on healthy lifestyle changes and important disease risk factors such as smoking, high blood pressure, and high cholesterol."

With an interest in describing how differing definitions of prediabetes might characterize the risks of prediabetes and diabetes in older adults, Selvin and a team of colleagues designed the current study as a prospective cohort analysis of adults without diabetes at baseline from within the ARIC study. From the ARIC study, investigators obtained data related to 3412 adults patients without diabetes at baseline and follow-up data from visit 5 of the study.

The specific prediabetes definitions of interest for the analysis were an HbA1c level of 5.7-6.4%, an impaired fasting glucose level of 100-125 mg/dL, either, or both. All of these were used as exposures in final analyses. The outcome of interest for the study was incident total diabetes, which was based on the presence of a physician diagnosis, glucose-lowering medication use, HbA1c level of 6.5% or more, or a FG level 126 mg/dL or more.

The mean age of the study cohort was 75.6 (SD, 5.2) years, 60%) were women, and 17% were Black. Of the 3412 patients, 1490 had HbA1c-defined prediabetes, 1996 had IFG-defined prediabetes, 2482 met either definition, and 1004 met both definitions of prediabetes. During the 6.5-year follow-up period, investigators identified a total of 156 incident cases of diabetes and 434 deaths.

Among those meeting the HbA1c definition of prediabetes, 97 (9%) progressed to diabetes, 149 (13%) regressed to normoglycemia, and 207 (19%) died. Among those meeting the IFG definition of prediabetes, 112 (8%) progressed to diabetes, 647 (44%) regressed to normoglycemia, and 236 (16%) died.

Further analysis indicated 17% (n=230) of patients with baseline HbA1c levels below 5.7% at baseline progressed to 5.7-6.4% during the follow-up period and 3% (n=41) developed diabetes. Additionally, 8% (n=80) progressed to meeting criteria for IFG-defined prediabetes and 3% (n=26) developed diabetes.

In an invited commentary penned by Kenneth Lam, MD, and Sei Lee, MD, MAS, of the Division of Geriatrics at the University of California, authors noted the importance of recognizing how the changing definitions of diabetes and prediabetes should be considered when caring for older adults.

“Focusing on risk factors, such as prediabetes, is high-value and appropriate in a middle-aged population. However, for many older adults, new-onset diabetes will often be mild and asymptomatic and only one of many potentially life-threatening conditions,” wrote the pair. “This study shows that identifying prediabetes in older adults should be regarded as a low priority, as it rarely leads to incident diabetes or adverse outcomes. To ensure high-value care for older adults, we should focus our care and research on what matters most to older adults and deprioritize twice-removed risk factors, such as prediabetes.”

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