USPSTF Finds Evidence Insufficient for Routine MCI Screening

Batya Swift Yasgur, MA, LSW

September 17, 2019

The US Preventive Services Task Force (USPSTF) has released a draft recommendation in which it concludes that the "current evidence is insufficient to assess the balance of benefits and harms of screening for cognitive impairment in older adults."

The recommendation applies specifically to community-dwelling older adults (aged ≥65 years) who do not have "recognized signs or symptoms of cognitive impairment."

"The draft recommendation is consistent with the 2014 final recommendation and, while the Task Force was encouraged to see some new research on this topic, there was still not enough evidence to recommend for or against screening for cognitive impairment in older adults," Task Force member Seth Landefeld, MD, chairman, Department of Medicine, University of Alabama at Birmingham, told Medscape Medical News.

"Although it is frustrating that there is once again not enough evidence to make a recommendation, the Task Force is continuing to call for more research in order to make a strong, evidence-based recommendation," said Landefeld, who also holds the Spencer chair in medical science leadership at the University of Alabama and serves on the board of directors of the American Board of Internal Medicine.

The draft recommendation, which is now available for public input, and the evidence review on which the recommendations are based were published online September 10.

New Research

"While cognitive impairment is a growing problem due to the aging American population, there are currently no professional organizations that recommend screening for cognitive impairment in older adults without signs or symptoms," Landefeld said.

The Task Force was "encouraged to see some new research on this topic [since 2014] to ascertain if new evidence was available to inform this decision," he said.

Family, friends, or clinicians may detect "subtle" signs and symptoms, leading to an assessment by a clinician, but such assessments are not considered screening and therefore were not the focus of the recommendation.

The recommendation was based on a systematic review of studies of the benefits and harms of screening for both mild cognitive impairment (MCI) and mild to moderate dementia. The studies covered the accuracy of screening instruments, the benefits of early intervention and treatment, and the potential harms of screening and treatment.

MMSE Superior

The review identified 59 studies that evaluated 49 screening instruments to detect cognitive impairment (n = 11,972 patients; mean age of participants, 68 – 90 years). Most of the instruments were "very brief" or "brief" (≤5 minutes or ≤10 minutes, respectively).

The most evaluated instrument (30 studies) was the Mini–Mental Status Examination (MMSE), with a sensitivity of .89 (95% confidence interval, .85 – .92) and a specificity of .90 (.86 – .93) in detecting dementia.

Fewer studies evaluated the other screening instruments. The ability of these instruments to detect dementia "varied widely," with sensitivities ranging from .43 to 1.0 and specificities ranging from .54 to 1.0.

All of the instruments were more accurate in detecting dementia than MCI.

No Clear Improvement

No trials investigated the direct effect of screening for cognitive impairment on any patient or caregiver outcomes, including those that might inform decision making, the authors note.

The 48 trials (n = 22,431 patients) that evaluated the effects of the acetylcholinesterase inhibitors (AChEIs) donepezil and galantamine and the drug memantine found that these agents improved measures of global cognitive function in the short term, albeit the magnitude of change was small. The changes were not sustained in the long term.

Most of the studies of these pharmacologic agents involved patients with dementia — particularly patients with moderate rather than mild dementia — and, most commonly, those with Alzheimer disease (AD).

Other medications or supplements were evaluated in 29 trials (n = 6489 patients), but none of these interventions yielded improvement in global cognition or physical function in patients with mild to moderate dementia or MCI.

The trials (n = 61 trials; 7847 patients) that evaluated nonpharmacologic patient-level interventions found "no clear improvement" in global or domain-specific measures of cognitive function in those who received the intervention in comparison with control participants at 3 months to 2 years of follow-up.

However, some trials found that psychoeducation and case management interventions (n = 58 and n = 17 trials, respectively) yielded improvements in caregiver burden and caregiver depression.

"Overall, the body of evidence on the potential benefits of screening for cognitive impairment is limited by several factors [including] the short duration of most well as the heterogeneous nature of interventions and inconsistency in the outcomes reported, which make cross-study comparisons difficult," the authors summarize.

Moreover, "no interventions specifically targeted a screen-detected population," and "most of the evidence suggesting improvement is applicable to persons with moderate dementia; thus, its applicability to a screen-detected population is uncertain."

Potential Harm

No studies "directly addressed the potential harms" of screening for cognitive impairment. However, 48 randomized clinical trials (n = 22,431 patients) and three observational studies investigated the harms of treatment with AChEIs and memantine. In these trials, "adverse effects of medications were common," they write.

In particular, among patients taking AChEIs, rates of adverse effects were "significantly higher," and more patients who received these agents withdrew from studies or discontinued their medication in comparison with patients who received placebo.

Memantine was "better tolerated, with no increase in adverse effects or withdrawal rates, compared with placebo."

Although overall, no increase in serious events was reported among patients taking AChEIs, individual studies reported increased rates of bradycardia, syncope, falls, and the need for pacemaker placement.

There was no "clearly significant" increase in harms in patients who received other medication or supplements, compared with control persons, in those trials (n = 21 trials; 5688 patients).

"Little harm" was found in nonpharmacologic interventions (n = 15 trials; 2874 patients).

"Research is especially important in two areas," Landefeld commented. "First is to discover treatments that will prevent or reverse cognitive impairment and that will prevent its progression, and second is to help determine how screening and early detection can support healthcare decision making and planning for patients, their families, and their clinicians," he said.

Thorough Cognitive Evaluation

Commenting on the study for Medscape Medical News, Keith Fargo, PhD, director of scientific programs and outreach at the Alzheimer's Association, who was not involved with the study, said that, given the fact that the USPSTF recommendation is "essentially unchanged since its 2014 report, the Alzheimer's Association's position remains that individuals who are concerned about their memory — or a loved one's memory — should make an appointment with their healthcare provider for a thorough cognitive evaluation."

He noted that there are "many reasons why someone might experience memory issues.... A routine screening will not provide sufficient information to know the cause of an individual's memory issues."

For that reason, "the Alzheimer's Association supports thorough cognitive assessments for older adults in a medical setting on a yearly basis so that accurate detection of abilities and changes can be made."

He reported that the Alzheimer's Association "successfully campaigned to get cognitive assessments covered by Medicare, as part of the Medicare Annual Wellness Visit, so costs will be covered for people on Medicare."

Landefeld added, "The Task Force continues to encourage clinicians to remain alert for signs and symptoms of cognitive impairment and talk with patients and families about any concerns they have."

The draft recommendation will remain open for public comment until 8:00 PM on October 7, 2019.

The report is based on research conducted by the Kaiser Permanente Research Affiliates Evidence-based Practice Center under contract to the Agency for Healthcare Research and Quality. No author disclosures were listed. Fargo has disclosed no relevant financial relatioships.

USPSTF. Published online September 10, 2019. Draft recommendation, Full text; Draft evidence review, Full text

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