The U.S. Preventive Services Task Force has deemed the current evidence “insufficient” to make a recommendation in regard to screening for cognitive impairment in adults aged 65 years or older.
“More research is needed on the effect of screening and early detection of cognitive impairment on important patient, caregiver, and societal outcomes, including decision making, advance planning, and caregiver outcomes,” wrote lead author Douglas K. Owens, MD, of Stanford (Calif.) University and fellow members of the task force. The statement was published in JAMA.
To update a 2014 recommendation from the USPSTF, which also found insufficient evidence to properly assess cognitive screening’s benefits and harms, the task force commissioned a systematic review of studies applicable to community-dwelling older adults who are not exhibiting signs or symptoms of cognitive impairment. For their statement, “cognitive impairment” is defined as mild cognitive impairment and mild to moderate dementia.
Ultimately, they determined several factors that limited the overall evidence, including the short duration of most trials and the heterogenous nature of interventions and inconsistencies in outcomes reported. Any evidence that suggested improvements was mostly applicable to patients with moderate dementia, meaning “its applicability to a screen-detected population is uncertain.”
Updating 2014 recommendations
Their statement was based on an evidence report, also published in JAMA, in which a team of researchers reviewed 287 studies that included more than 285,000 older adults; 92 of the studies were newly identified, while the other 195 were carried forward from the 2014 recommendation’s review. The researchers sought the answers to five key questions, carrying over the framework from the previous review.
“Despite the accumulation of new data, the conclusions for these key questions are essentially unchanged from the prior review,” wrote lead author Carrie D. Patnode, PhD, of the Kaiser Permanente Center for Health Research in Portland, Ore., and coauthors.
Of the questions – which concerned the accuracy of screening instruments; the harms of screening; the harms of interventions; and if screening or interventions improved decision making or outcomes for the patient, family/caregiver, or society – moderate evidence was found to support the accuracy of the instruments, treatment with acetylcholinesterase inhibitors and memantine for patients with moderate dementia, and psychoeducation interventions for caregivers of patients with moderate dementia. At the same time, there was moderate evidence of adverse effects from acetylcholinesterase inhibitors and memantine in patients with moderate dementia.
“I think, eventually, there will be sufficient evidence to justify screening, once we have what I call a tiered approach,” Marwan Sabbagh, MD, of the Cleveland Clinic Lou Ruvo Center for Brain Health in Las Vegas, said in an interview. “The very near future will include blood tests for Alzheimer’s, or PET scans, or genetics, or something else. Right now, the cognitive screens lack the specificity and sensitivity, and the secondary screening infrastructure that would improve the accuracy doesn’t exist yet.
“I think this is a ‘not now,’ ” he added, “but I wouldn’t say ‘not ever.’ ”
Dr. Patnode and coauthors noted specific limitations in the evidence, including a lack of studies on how screening for and treating cognitive impairment affects decision making. In addition, details like quality of life and institutionalization were inconsistently reported, and “consistent and standardized reporting of results according to meaningful thresholds of clinical significance” would have been valuable across all measures.