Most cases of prediabetes in older adults did not progress to diabetes, study finds

A cohort study of older adults found a high prevalence of prediabetes, but during more than six years of follow-up, death or regression to normoglycemia was more common than progression to diabetes.

Prediabetes may not be a useful diagnostic indicator in older age, researchers concluded, after a community-based cohort study found that prediabetes regressed to normoglycemia or death more frequently than progressing to diabetes.

Researchers used the Atherosclerosis Risk in Communities Study to conduct a prospective cohort analysis of adults who were ages 71 to 90 years and free of diabetes at baseline. Four definitions of prediabetes were assessed: an HbA1c level of 5.7% to 6.4%, impaired fasting glucose level (100 to 125 mg/dL [5.6 to 6.9 mmol/L]), either, or both. Diabetes was defined by physician diagnosis, glucose-lowering medication use, HbA1c level of 6.5% or greater, or fasting glucose of 126 mg/dL (7.0 mmol/L) or greater. Results were published online Feb. 8 by JAMA Internal Medicine.

Of 3,412 participants at baseline, 2,497 attended a follow-up visit or died. During the 6.5-year follow-up period, there were 156 incident total diabetes cases (118 diagnosed) and 434 deaths. A total of 1,490 participants (44%) had HbA1c levels of 5.7% to 6.4%, 1,996 (59%) had impaired fasting glucose, 2,482 (73%) met either criteria, and 1,004 (29%) met both criteria.

Among participants with HbA1c levels of 5.7% to 6.4% at baseline, 97 (9%) progressed to diabetes, 148 (13%) regressed to normoglycemia (HbA1c level <5.7%), and 207 (19%) died. Of those with impaired fasting glucose at baseline, 112 (8%) progressed to diabetes, 647 (44%) regressed to normoglycemia (fasting glucose level <100 mg/dL [5.6 mmol/L]), and 236 (16%) died. Of those with baseline HbA1c levels less than 5.7%, 239 (17%) progressed to HbA1c levels of 5.7% to 6.4% and 41 (3%) developed diabetes. Of the 1,035 participants with baseline fasting glucose levels less than 100 mg/dL (5.6 mmol/L), 80 (8%) progressed to impaired fasting glucose, 26 (3%) developed diabetes, and 198 (19%) died.

The study authors observed that fewer than 12% of older adults progressed from prediabetes to diabetes during the follow-up period, regardless of the definition used. In addition, they noted that a substantial proportion of individuals with prediabetes at baseline regressed to normoglycemia and that normoglycemia or death was more common than progression to diabetes during the study. They wrote, “The current study further highlights the potential futility of aggressive diabetes screening in older adults given the very low rates of diabetes progression among those with prediabetes.”

An accompanying editorial commentary made several clinical recommendations based on the results, including that “in older adults with frailty and limited life expectancy, prediabetes is irrelevant and can safely be ignored.” For healthy patients ages 75 years or older, the editorialists recommended that prediabetes be lower priority than symptomatic conditions or traditional risk factors. “Diagnosing prediabetes and then expending time and effort discussing management strategies should not come at the expense of attending to other issues of immediate importance to the patient. For all but the healthiest of older adults older than 75 years, the current recommendations for annual monitoring and weight loss are likely low yield,” they wrote.