More evidence-based research is needed before the U.S. Preventive Services Task Force can recommend that clinicians screen their older patients for cognitive impairment such as dementia and Alzheimer’s disease.
Cognitive impairment is a growing public health dilemma that affects millions of Americans as they age. The Global Burden of Disease study shows that Alzheimer’s rose from the 12th most burdensome disease or injury in the United States in 1990 to the 6th in 2016.
Medical experts who were commissioned to conduct an evidence report for the Task Force projected that the burden of Alzheimer’s disease is expected to grow to 13.8 million U.S. residents by 2050 — or nearly 3.3% of the projected U.S. population by that year.
The symptoms of cognitive impairment can range from problems with memory and language, to learning new things or making decisions that affect everyday life.
“Early identification of cognitive impairment through screening would ideally allow patients and their families to receive care at an earlier stage in the disease process, potentially facilitating discussions regarding health, financial, and legal decision-making while the patient still retains decision-making capacity,” the authors of the Task Force evidence report wrote.
But after reviewing some 287 studies including more than 285,000 older adults, the Task Force determined there wasn’t sufficient evidence about the benefits or harms of screening adults 65 and older who do not have signs or symptoms. The Task Force also did not find adequate evidence that screening for cognitive impairment improves decision-making or planning by patients, caregivers or doctors.
At the same time, there is little evidence on potential harms of screening, such as depression, anxiety or lower quality of life.
“Given the burden of dementia and the intense public interest in preventing cognitive impairment, the lack of progress is disheartening,” Carol Brayne, MD, with the Department of Public Health and Primary Care at the University of Cambridge in the UK, wrote in an accompanying JAMA editorial to the Task Force evidence report.
But, she added, “Political considerations and pressure from commercial interests and patient advocacy groups notwithstanding, public policies for dementia screening should be supported by evidence.”
The Task Force — an independent panel of national experts in prevention and evidence-based medicine — encourages clinicians to remain alert for early signs of symptoms of cognitive impairment, while calling for more research on the detection of dementia.
“Research is especially needed on whether screening and early detection of cognitive impairment helps patients, caregivers, and doctors make decisions about health care or plan for the future,” said Douglas K. Owens, chair of the Task Force and the director of Stanford Health Policy. “We share the frustration of clinicians who want to offer something that could help patients prevent cognitive impairment. We hope that additional research will enable us to know whether that’s possible.”
The most commonly used screening tests include the Mini-Mental State Examination as well as the clock-drawing test. Screening tests involve asking patients to perform a series of tasks that asses one or more aspects of cognitive functions. The USPSTF concluded that more research is needed to know whether such screening tests can lead to interventions that help prevent or improve cognitive impairment.