System Gauges Dementia Risk Among Diabetics

Nancy A. Melville

August 19, 2013

Researchers have developed a simple scoring system for determining the risk for dementia associated with type 2 diabetes, using the medical data of a large cohort of nearly 30,000 patients over the age of 60 years with the disease.

"To the best of our knowledge, our study is the first to describe a diabetes-specific dementia risk score," write the authors.

"Furthermore, we identified additional determinants of dementia in diabetic patients, for instance, cardiovascular disease and diabetic foot."

The study of 29,961 records of patients in the Northern California–based Kaiser Permanente system with type 2 diabetes showed that 5173 (17%), or about 1 in 5, patients developed dementia within 10 years of entry into the study, which is consistent with known rates of dementia in the diabetes population.

In assessing the patients' medical records using criteria of 45 candidate risk factors, the researchers found the leading risk factors to be most associated with dementia to include age, education level, and diabetes-related factors, including acute metabolic event, microvascular disease, diabetic foot, cerebrovascular disease, heart disease, and depression.

"The identification of new predictors specific to diabetes [such as cardiovascular disease and diabetic foot] in this study emphasizes the importance of creating a risk score specifically for patients with type 2 diabetes," the authors wrote.

The findings were published online August 19 in Lancet Diabetes & Endocrinology, a new Lancet specialty journal making its debut this week.

Under the type 2 diabetes–specific dementia risk score (DSDRS) system, patients were allocated into 1 of 14 categories according to their degree of risk, from the lowest score (-1) to the highest risk (12–19).

Those with the highest scores had a risk for dementia that was 15 times greater than the lowest scores. In the study, scores above 11, in the highest risk category, were fairly rare, the authors noted.

The scoring system allows for the relatively easy assessment of a patient's risk for dementia in a primary-care setting, avoiding the need for more time-consuming and costly measures such as cognitive testing or brain imaging, said coauthor Rachel Whitmer, PhD, an investigator with the Kaiser Permanente division of research, in Oakland, California.

"I think it lets clinicians know that these patients should be on their radar for a number of different reasons," she told Medscape Medical News.

"For one thing, [those with the higher scores] may be more likely to show up with some cognitive or memory problems, and this could affect their ability to self-care with a chronic condition, such as adhering to medication, or they may be at a greater risk for low or high blood sugar episodes.

"And in terms of science in general, I think this helps us to better understand why this population has double the risk of getting dementia — what it is about diabetes that appears to affect their brain health?"

Some of the study's key limitations include the use of diagnostic codes for dementia rather than a standardized assessment, and while as many as 45 potentially predictive risk factors were included, additional predictors could improve the model's predictability, such as APOE genotype or MRI abnormalities, the authors said.

Anna-Maija Tolppanen, PhD, from the University of Eastern Finland, Kuopio, who wrote a commentary accompanying the study, noted that, while evidence is lacking on measures that could be effective in actually preventing dementia once patients are found to be at a higher risk, interventions from other diseases may hold some clues.

"Dementia shares many cardiovascular risk factors with other chronic diseases such as diabetes and cardiocerebrovascular diseases, and interventions on these risk factors have already been shown to be efficient for preventing or delaying cardiovascular diseases and/or type 2 diabetes risk," she told Medscape Medical News.

Findings from 3 ongoing European randomized controlled trials on the prevention of dementia should help shed more light on the issue, she added.

"The results of the ongoing dementia trials should be available within the next 2 years. The risk score described [in the new study] can be used to choose persons with high dementia risk to participate in these kind of trials.

"Later, if a preventive treatment should be available, it could be used for targeting the intervention toward those who are particularly susceptible."

The study received funding from Kaiser Permanente Community Benefit, National Institutes of Health, Utrecht University, ZonMw, and Fulbright. Dr. Whitmer has reported no financial relationships. Disclosures for the coauthors are listed in the article. Dr. Tolppanen has reported no financial relationships.

Lancet Diabetes Endocrinol. Published online August 19, 2013. Abstract


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