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Evidence on Cognitive Impairment Screening in Older Adults Is Insufficient, Panel Says

‚ÄčShould adults older than 65 be screened for cognitive impairment if they are asymptomatic? Not necessarily, according to a US Preventive Services Task Force (USPSTF) recommendation statement, which suggested that the current evidence is insufficient to recommend whether cognitive impairment screening should be used to assess community-dwelling, asymptomatic older adults.

"The evidence is lacking, and the balance of benefits and harms of screening for cognitive impairment cannot be determined," wrote Douglas K. Owens, MD, MS, chair of the USPSTF, and colleagues.

The recommendation, published on February 25, 2020 in JAMA, serves as an update to the 2014 recommendation by the USPSTF. The task force had requested a review of the literature on cognitive impairment screening, including mild to moderate dementia and mild cognitive impairment among asymptomatic, community-dwelling adults older than 65. The new statement is consistent with the 2014 USPSTF recommendation.

"Early detection of cognitive impairment can allow for identification and treatment of reversible causes, may help clinicians anticipate problems patients may have in understanding and adhering to medical treatment plans, and may also be useful by providing a basis for advance planning on the part of patients and families," the USPSTF panel wrote.

Clinicians should be aware of early symptoms or signs of cognitive impairment, like problems with language or memory, and evaluate patients accordingly, they added.

The panel based its recommendation on a review of published research through January 2019. The review included evidence on the harms and benefits of interventions and treatment for older adults with cognitive impairment and their caregivers and the accuracy of screenings in identifying cognitive impairment.  

Only one randomized clinical trial assessed the utility of screening for cognitive impairment in a primary care setting among community-dwelling older adults, noted Ronald C. Petersen, PhD, MD, FAAN, of Mayo Clinic in Rochester, Minnesota and Kristine Yaffe, MD, of University of California, San Francisco in an accompanying editorial. While the trial did not show any harm or benefit from screening for cognitive impairment, it failed to resolve several of the questions it was intended to address, they wrote.

Only 34 percent of the 134 trial participants who screened positive for dementia were subsequently evaluated. These data likely had limited statistical power to determine differences in outcomes and may be indicative of other underlying differences in pursuing an assessment, like the degree of impairment, Drs. Peterson and Yaffe pointed out.

Inasmuch as the participants were followed for up to one year, it may be difficult to explain any effect on decision-making, caregiver, societal, or patient-family outcomes in relatively few participants over a short period, they added.

Although the studies reviewed do not collectively offer strong support for screening for treatment or cognitive impairment of cognitive deficits, the lack of evidence in the existing literature does not mean that screening is not beneficial at all, the editorialists noted.

 "It would be a mistake if clinicians did not consider the value of screening for cognitive impairment on a case-by-case basis. With the development of disease-modifying therapies for some of the underlying neurodegenerative diseases that contribute to cognitive impairment, the importance of screening will become increasingly apparent," wrote Drs. Petersen and Yaffe.

In another editorial published in JAMA Internal Medicine, Carol Brayne, MD, of the University of Cambridge in the United Kingdom wrote that clinicians and patients often assume that cognitive impairment screening is beneficial, which is concerning given the lack of evidence.

Dr. Brayne pointed out that a policy in the United Kingdom required older adults with unplanned hospital admissions to be screened for dementia, but it has since been withdrawn due to lack of clarity regarding benefit.

The USPSTF also emphasized the dearth of evidence about the harm of diagnosing dementia, apart from the known common adverse effects of prescription drugs, Dr. Brayne said. "The discussion of the potential harms of diagnosing dementia should also include uncertainty about the meaning of a diagnosis and the inability to accurately advise patients about prognosis," Dr. Brayne wrote.

"Risk reduction for cognitive impairment includes stopping smoking and moderating alcohol intake; promoting healthful diet and physical activity; and preventing and managing hypertension, cardiovascular disorders, diabetes, and depression," Dr. Brayne continued. "Clinicians can recommend these approaches to reduce risk to all older adults without the need for any cognitive screening."

The American Academy of Neurology suggests using validated, brief cognitive assessment instruments to evaluate for cognitive impairment and has established guidance for detecting cognitive impairment during yearly wellness visits.

The Agency of Healthcare Research and Quality provided funding for the review. Dr. Owens reported no relevant disclosures. Dr. Yaffe disclosed relationships with US Department of Veterans Affairs, Doris Duke Charitable Funds, Alector, National Institute on Aging, Eli Lilly, the Global Council of Brain Health, Beeson Scholars Program, US Department of Defense, and the Alzheimer Disease Drug Discovery Fund. Dr. Petersen disclosed relationships with Mayo Clinic Foundation for Medical Education and Research, National Institute on Aging, GHR Foundation, GE Healthcare, Eisai, Genentech, Biogen, Roche, and Merck.


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