Determining What Prediabetes Means in Older Adults
Recent research suggests that we need better ways to assess the risk of future type 2 diabetes (T2D) in older adults. People with blood glucose (sugar) levels higher than normal but lower than the levels used to define diabetes are said to have “prediabetes,” because they are known to be at increased risk for the disease. Fortunately for those at high-risk, the landmark NIDDK-led Diabetes Prevention Program (DPP) clinical trial demonstrated that T2D can often be prevented or delayed through diet and exercise changes designed to yield modest weight loss. This DPP lifestyle intervention was particularly effective in older DPP participants, and the infrastructure to provide a group-based adaptation of the approach has increased nationally in recent years. Targeting those programs to people most likely to benefit from them depends on knowing who has a high likelihood of developing diabetes. There are standard definitions for prediabetes using different measurements that work fairly well for individuals who are middle aged or younger, but less is known about how well they predict the development of T2D among older individuals.
Researchers therefore studied a 3,412-person group of volunteers without diabetes (60 percent female; 17 percent Black; 83 percent White) who had an average age of about 75. The study tested different diagnostic criteria for prediabetes to compare how well they worked in older adults: using “HbA1c” levels; using fasting glucose levels; using either HbA1c or fasting glucose levels; or requiring the criteria for both measures to be met. The proportion of participants diagnosed with prediabetes differed greatly depending on which criteria were applied: 29 percent if using both HbA1c and fasting glucose, 44 percent based on HbA1c levels alone, 59 percent using fasting glucose levels alone, and 73 percent according to at least one of the two measures. As expected, a higher proportion of the individuals meeting one or more criteria for prediabetes developed T2D than those who did not have prediabetes at the outset. However, for each of the individual prediabetes definitions, more of the volunteers saw their glucose or HbA1c levels improve to the normal range than progress to the diabetes range. Further, those considered to have prediabetes were also less likely to develop T2D than they were to die of any cause. Taken together, these findings suggest the need for a better test to identify future diabetes risk in people over age 70.
Rooney MR, Rawlings AM, Pankow JS,...Selvin E. Risk of progression to diabetes among older adults with prediabetes. JAMA Intern Med 181:511-519, 2021.