Older people classified as ‘prediabetic’ rarely progress to complete diabetes

According to a study by researchers at the Johns Hopkins Bloomberg School of Public Health, older people classified as having “prediabetes” due to moderately high blood sugar readings usually do not develop full-blown diabetes.

Doctors still view prediabetes as a useful indicator of future diabetes risk in young and middle-aged adults. However, the study, which followed nearly 3,500 older people, with a median age of 76, for about six and a half years, suggests that prediabetes is not a useful marker of diabetes risk in people with diabetes. ‘an older age.

The results were published on February 8 in JAMA Internal Medicine.

“Our results suggest that for older adults whose blood sugar levels are in the prediabetes range, few will actually develop diabetes,” says lead study author Elizabeth Selvin, PhD, professor in the Department of Bloomberg School Epidemiology. “The prediabetes category does not seem to help us identify those at high risk. Instead, doctors should focus on healthy lifestyle changes and important disease risk factors such as smoking, high blood pressure and hypercholesterolemia. “

Type 2 diabetes leads to chronic excessive glucose levels in the blood, which damages organs, including the kidneys, weakens the immune system and damages blood vessels, leading to heart disease and stroke, among others. The prevalence of diagnosed type 2 diabetes in the United States has risen from less than 1% in the 1950s to over 7% today – and researchers believe the true figure, including undiagnosed diabetes, now exceeds 12%. This sharp increase is due to the aging of the American population and the increasing rates of overweight and obesity.

Doctors have used the concept of prediabetes – involving blood glucose levels above normal but not yet in the diabetic range – as an indicator of a high risk of diabetes in younger and middle-aged people. However, the usefulness of the concept among the elderly – particularly those 70 and over – has been less clear.

“It’s very common for older people to have at least slightly elevated blood sugar, but the likelihood of them progressing to diabetes remains an unresolved question,” says Selvin.

To get a better idea of ​​how older people with prediabetes are doing, Selvin and his colleagues turned to the study on the risk of atherosclerosis in communities. This large epidemiological cohort project, funded by the US National Heart, Lung, and Blood Institute and including black and white participants, has been underway in four American medical centers, including Johns Hopkins, since 1987. For their analysis of the prediabetes, the researchers selected 3,412 participants in the ARIC study who had attended a follow-up visit in 2011-13 – at a time when participants were between 71 and 90 years old – and had no history of diabetes. The researchers then examined how the participants’ blood sugar readings changed during the next follow-up visit in 2016-17.

As expected, the researchers found that “prediabetes,” defined by two different measures of blood tests, was very common among participants in the 2011-13 visit. People with prediabetes, defined as moderately elevated blood glucose levels after an overnight fast (the impaired fasting blood sugar test, or IFG), accounted for 59% of the initial sample, and those with prediabetes defined with a different blood test for glycated hemoglobin (HbA1c), represented 44 percent of the original sample.

However, the results showed that only a small number of participants who had prediabetes in 2011-13 had developed diabetes at the time of the 2016-2017 visit – 8% of IFG-defined prediabetics and 9% of defined prediabetics. by HbA1c. prediabetic.

In contrast, 44% of the IFG group and 13% of the HbA1c group had improved enough during the 2016-2017 visit that their test results returned to the normal range. In addition, 16 and 19 percent of these two groups had died from other causes during the 2016-2017 visit.

The results show that older people with prediabetes, at intervals like the one in the study, are more likely to have lower blood sugar – or die for other reasons – than to progress to diabetes.

“It seems that in older people, ‘prediabetes’ just isn’t a solid diagnosis,” says Selvin.

“Our results support the focus on improving lifestyle, including exercise and diet when feasible and safe, for older adults with prediabetes,” says Mary Rooney, PhD, intern postdoctoral fellow at Bloomberg School and first author of the article. “This approach has great benefits for patients.”

Selvin and his colleagues recommend that for older adults, doctors should focus their screening efforts on risk factors, such as hypertension, that are more useful in predicting illness and death in this population.