USPSTF: Evidence Insufficient for Routine Dementia Screening

Pauline Anderson

November 04, 2013

There is still not enough clear evidence to recommend routine screening for dementia, a draft recommendation  posted today by the US Preventive Services Task Force (USPSTF) concludes.

The new recommendation was based on a systematic review of literature on the topic published online October 22 in the Annals of Internal Medicine, reported by Medscape Medical News at that time.

But while the overall evidence on routine screening is insufficient, clinicians should remain alert to early signs or symptoms of cognitive impairment and evaluate accordingly, the USPSTF said in a statement.

The draft recommendation applies to adults over age 65 years without signs or symptoms of cognitive impairment. It will be posted on the USPSTF Web site and be open for public comment before the Task Force develops a final recommendation.

This recommendation updates the 2003 USPSTF statement that also concluded that the evidence was insufficient to recommend for or against routine screening for dementia. Unlike that earlier recommendation, this updated version considered the evidence on screening for and treatment of mild cognitive impairment in addition to dementia, and on how screening affects decision-making and planning.

Brief Screening Tools

With new data on screening accuracy, the Task Force was able to conclude that there is adequate information on the accuracy of some brief screening tools to identify dementia. The most widely studied instrument is the Mini-Mental State Examination. For the most commonly reported cut points (23/24 or 24/25), the pooled sensitivity from 14 studies was 88.3% (95% confidence interval [CI], 81.3% - 92.9%) and specificity was 86.2% (95% CI, 81.8% - 89.7%).

Other screening tools include the Clock Draw Test, Mini-Cog, Memory Impairment Screen, Abbreviated Mental Test, Short Portable Mental Status Questionnaire, Free and Cued Selective Reminding Test, 7-Minute Screen, Telephone Interview for Cognitive Status, and Informant Questionnaire on Cognitive Decline in the Elderly. These tests have reasonable test performance according to some studies, but their sensitivity or specificity ranged widely and optimal diagnostic cut-points for many are unclear, the statement said.

The new data suggest that treatment of mild to moderate dementia with acetylcholinesterase inhibitors (AChEIs) and memantine, and with nonpharmacologic interventions, such as cognitive stimulation and exercise, results in small improvement in cognitive function, and that interventions aimed at caregivers result in reduced caregiver burden and depression. However, the clinical significance of these improvements is uncertain, according to the Task Force report.

No published evidence was found on the effect of screening on decision-making or planning by patients, clinicians, or caregivers, the Task Force concluded.

Critical Gap

"This is a critical gap in the evidence, and more research is needed so we can better understand the benefits and risks of screening and understand the impact early detection can have on the lives of patients and their families," commented Task Force member Douglas K. Owens, MD, in press materials accompanying the draft document.

More data will be required before such screening could be recommended. "If we had information on treatments that might be available in early dementia that were highly effective, I think that would be one thing," Task Force co-vice chair Albert Siu, MD, told Medscape Medical News. "And, if we found interventions that would be effective in terms of helping individuals with early dementia and their family members to make decisions and plan, we would consider that to be important evidence."

The Task Force also determined that there is inadequate evidence on nonpharmacologic interventions and on the harms of screening (eg, the impact of labeling and of false-positive results). There is, however, evidence that AChEIs are associated with adverse events, some of which are serious, for example, central nervous system disturbances and arrhythmia.

"Overall, the USPSTF was unable to estimate the balance of benefits and harms of screening for cognitive impairment," the draft recommendation statement concludes.

The Task Force noted that no professional organization has formal guidelines on screening for dementia or cognitive impairment. However, earlier this year, the Alzheimer's Association published guidance on the detection of cognitive impairment during the Annual Wellness Visit and recommended an algorithm starting with a health risk assessment, patient observation, and unstructured questioning. Use of a brief structured assessment is recommended if signs or symptoms of cognitive impairment are present or if an informant is unavailable to confirm the absence of signs or symptoms.

Dr. Siu noted that dementia screening for patients showing signs and symptoms of dementia was beyond the scope of the Task Force review. "The scope was what do you do on a population basis for individuals who are not complaining of any symptoms and there have been no signs," he said. "The question is, should you be automatically screening these people? Certainly, if someone comes in with signs or symptoms, that requires evaluation."

Dementia affects up to about 5.5 million Americans. Its prevalence increases with age, affecting 5% in those aged 71 to 79 years, 24% in those aged 80 to 89 years, and 37% in those older than age 90 years.

The estimated total health, long-term care, and hospice care costs for dementia in the United States were $183 billion in 2011. These costs don't include the estimated $202 billion in uncompensated care that informal caregivers provide annually.

"Dementia is a very serious issue that has a significant impact on the lives of older adults and their families," said Dr. Siu in the press statement. "Although the benefits and harms of what we can offer patients through routine screening are unclear right now, clinicians should remain alert to early signs or symptoms of cognitive impairment and evaluate their patients as appropriate."

The Task Force is now providing an opportunity for public comment on the draft recommendation until December 2. All public comments will then be considered as the Task Force develops its final recommendation. Dr. Siu expects a final recommendation in the spring of 2014.

"Regardless of what our recommendation is, it will serve as guidance to physicians," rather than a directive, Dr. Siu told Medscape Medical News.

The Task Force is an independent, volunteer panel of national experts in prevention and evidence-based medicine that works to improve the health of all Americans by making evidence-based recommendations about clinical preventive services, such as screenings, counseling services, and preventive medications.

The proposed recommendation can be found here.

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