Simple tool can identify at-risk patients for dementia screening

By Rob Goodier

NEW YORK (Reuters Health) - Rating patients on a simple new checklist can help identify those who should undergo a dementia screen, according to new research.

Based on results gathered from four large ongoing cohort studies, the checklist includes seven items: age, education, history of stroke, diabetes, assistance managing money or medication, BMI, and depressive symptoms.

It amounts to a pre-screen for full screening that could be used in clinical settings if it is validated in future trials, researchers said.

"Our tool is designed to help clinicians identify a subset of older patients who may be at higher risk of cognitive impairment because of other factors. The goal is to strike a middle ground between screening everyone and screening no one by encouraging screening in these higher-risk patients," lead author Dr. Deborah Barnes, from the University of California, San Francisco, told Reuters Health by email.

"Sometimes the decision to screen for cognitive impairment is obvious - such as when a patient or family member expresses concern, or when a patient is a 'poor historian' and has difficulty recalling their medical history. But sometimes patients with dementia - especially those who are a little younger or have mild dementia - may not have any obvious signs or symptoms during a medical visit," Dr. Barnes said.

Dr. Barnes and her team published their findings online February 1 in Alzheimer's and Dementia.

Researchers from each of the four ongoing studies on which the tool is based independently analyzed their data to determine simple indicators for at-risk patients. Analysis found that the tool is accurate in all four cohorts: the Cardiovascular Health Study, the Framingham Heart Study, the Health and Retirement Study, and the Sacramento Area Latino Study on Aging, with a Harrell's C statistic between 0.68 and 0.78.

The tool gives patients a score from zero to 56.

It starts with the patient's age. At 80 years old and older patients should automatically undergo dementia screening, the researchers say, so their indicator includes patients ages 65 to 79, giving them one point for each year starting at age 65.

The next item is education. Add nine points for patients with less than 12 years of school. Then add eight points for patients with a BMI less than 18.5, six points for a history of stroke, three points for diabetes, and 10 points if the patient needs help handling money or taking medications. Finally, add six points for patients with depressive symptoms.

A cut point of 22 points is used to stratify people into high-risk and low-risk groups, the authors note.

The tools makes interesting use of four cohort studies, but is not recommended for clinical use until further study confirms its efficacy, said Dr. Chris Carpenter, from Washington University in St. Louis, Missouri, who was not involved in the study.

Dr. Carpenter's research has included the analysis of dementia screens in the emergency room.

"Efforts like this to develop more accurate and sufficiently simple instruments to screen for dementia are well worthwhile and should continue. The authors' model displayed impressive 'fit' across ethnic subsets and overall acceptable calibration," Dr. Carpenter said.

He offered a list of tests that remain before the tool might be used in clinical settings. Those include validation among different patient populations; data on accuracy that includes sensitivity, specificity, and likelihood ratios; regression analysis of the data; and prospective evaluation that includes an assessment of the tool's user friendliness, clinician acceptability, and impact on clinician behavior.

Dr. Barnes lacks funding to carry out clinical trials, but she would appreciate feedback from clinicians who use the tool, she said.

Dr. Barnes has developed another tool that predicts a patient's chances of progressing from mild cognitive impairment to Alzheimer's disease. This tool scores patients with a diagnosis of mild impairment on a 10-point scale and is described in the same issue of Alzheimer's and Dementia.

The scale includes information from a functional assessment, MRI, and the Alzheimer's Disease Cognitive Scale-cognitive subscale.

Patients who score zero to 3 on the scale have a 6% chance of progressing to Alzheimer's disease within three years. Those who score 4-6 points have a 53% chance of progression and those with 7-9 points have a 91% chance of progression, the study found.

SOURCES: http://bit.ly/1fYq335 and http://bit.ly/1jPmPj8

Alzheimers Dement 2014.

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