According to the U.S. Preventive Services Task Force (USPSTF), routine screening of all older individuals for cognitive impairment – or early warning signs of dementia – has no scientifically proven benefit.
The task force, which rigorously evaluates clinical research to assess the merits of preventive measures, such as screening tests and medications, analyzed evidence of benefits, harms and sensitivity of screening instruments for cognitive impairment in older adults. It concluded, as reported by MedPageToday.com, that a clear benefit for screening has not been established, relative to the potential for harm for people who are older than 65 and have no signs or symptoms of cognitive decline.
The panel reviewed 55 studies examining the accuracy of screening instruments, and more than 130 studies of interventions aimed at slowing or stopping cognitive decline in patients who tested positive for cognitive impairment. Its results were published in the Annals of Internal Medicine.
The report indicated that current drug treatments such as acetylcholinesterase inhibitors (drugs that impede certain enzymes from interfering with brain synapses) may have “a small effect on cognitive function measures in the short term for patients with mild to moderate dementia, but the magnitude of the clinically relevant benefit is uncertain.”
It was the same for interventions other than drugs. The task force concluded that trials of cognitive stimulation resulted in “inconsistent evidence,” and in trials showing some benefit, it was of only borderline clinical significance.
Bottom line: There’s insufficient evidence to draw a conclusion about the balance between benefits and risks of screening. And evidence for harms was lacking as well, but would certainly include drug side effects.
The USPSTF reviewed the issue in 2003, and more than 10 years later, its report is much the same. But the task force emphasized that the review covered only routine, universal screening for older patients without clear signs or symptoms of cognitive impairment.
According to MedPageToday, the Alzheimer’s Association disagrees with the don’t-bother conclusion of the task force. Medicare covers cognitive screening, and the association recommends that Medicare enrollees take advantage of it. But the American Geriatrics Society takes no position on cognitive screening if the patient or his or her caregivers have no complaints. But the society does recommend certain assessment and treatments approaches for patients selected for screening.
As usual, screenings should be customized – there is no one-size-fits-all approach. “There doesn’t seem to be, on a group basis, a clear way to decide whether there is sufficient benefit to justify screening,” one Alzheimer’s expert told MedPageToday, “but patients may think differently for themselves, and individual physicians may think differently.”
He said screening might help patients adopt lifestyle changes, such as lowering cholesterol and exercising, to reduce their chance of their impairment progressing. He also said that although anxiety resulting from a positive screen has been cited as a potential harm of screening, a study examined that issue and found little risk of that sort.
We’re not ready to accept that conclusion, as anxiety can be truly debilitating – see our blog, “Blood Test for Alzheimer’s Raises Thorny Questions.” And, as the MedPage story points out, one study in 2006 involved 3,573 individuals who were offered screening. Nearly all accepted, but of 434 with positive screening results, 207 refused a more definitive follow-up assessment, presumably because they didn’t really want a firm diagnosis.
Regarding drug therapy benefits, the USPSTF literature review from last year indicated improvements of 1.36 to 3.06 points in scores on the 70-point Alzheimer’s’ Disease Assessment Scale-Cognition (ADAS-Cog) test – a four-point improvement is the minimum for clinical relevance.
Regarding caregiver burden, interventions at the stage of mild impairment also appear to be of minimal benefit, according to the literature review. Data from two dozen studies of group, individual and telephone-based interventions showed statistical significance … but the clinical benefit was questionable.
Still, the panel offered some guidance for doctors who do choose to perform screening. It identified eight instruments that seem to be effective for identifying mild impairments in the primary care setting, which you can see by linking to the report; see the section labeled Screening Tests.
Our take-home message: The decision to test or not should be made on an individual basis after frank and clear discussions among the doctor, patient and caregivers.