High Rate of Undiagnosed Prediabetes Found in Patients with Alzheimer’s Disease

Greater than 40% of Alzheimer's patients had undiagnosed prediabetes

With R. Scott Turner MD, PhD

When researchers began enrolling patients with Alzheimer’s disease (AD) into a trial of a dementia medication, they found that more than 40% of patients had undiagnosed impaired glucose tolerance. 

 “The number of people with glucose intolerance was much higher than expected,” says R. Scott Turner, MD, PhD, Professor of Neurology and Program Director of the Memory Disorders Program at Georgetown University Medical Center in Washington, DC. “I was surprised by how many people didn’t know they were prediabetic, and these are individuals who already get the best medical care.”

“We know from animal studies that caloric restriction prevents diseases of aging such as diabetes and Alzheimer’s,” said Dr. Turner. “On the flip side of the coin, having diabetes increases one’s risk of developing AD. So, perhaps by improving glucose tolerance, we will prevent or delay both diabetes and Alzheimer’s."

Study design and findings

The phase II trial was designed to investigate the safety and tolerability of resveratrol for mild-to-moderate dementia due to AD and involved 128 patients recruited from and/or referred to specialty clinics. As part of the study design, all patients underwent a baseline oral glucose tolerance test after an overnight fast and 2 hours later.

Overall, 6% of patients had an impaired fasting glycemia (4%) or type 2 diabetes (2%), and 43% had impaired glucose tolerance (30%) or type 2 diabetes (13%) at the 2-hour test.

The study findings “add to the body of knowledge that there is a connection between diabetes and related disorders and Alzheimer’s disease, and we need to understand what that connection is so that we can potentially intervene,” commented Heather M. Snyder, PhD, Director of Medical and Scientific Operations at the Alzheimer’s Association. Dr. Snyder noted that the study involved a relatively small sample size with a broad range of Mini-Mental State Examination scores and a broader age range than most studies.

Should patients receive glucose testing at the time of alzheimer’s diagnosis?

Dr. Turner said that while glucose tolerance tests are not typically ordered by neurologists, the findings “suggest that perhaps we should test all our patients with early Alzheimer’s. It’s a simple, inexpensive study that reveals critical health information.”

Dr. Snyder said that though there is not currently enough information to change clinical practice, the findings “raise the question of whether when someone is diagnosed with AD and you know that they may have difficulty with medication management, should you then screen them for glucose intolerance or type 2 diabetes to help them with care in the treatment of metabolic diseases in the context of dementia.”

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