Citing a lack of data about the benefits and harms of screening, the US Preventive Services Task Force (USPSTF) has left unchanged the recommendations of its 2003 guidelines on cognitive impairment screening in older adults, according to an update published online ahead of print March 25 in the Annals of Internal Medicine.
“The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for cognitive impairment,” said Virginia A. Moyer, MD, MPH, in a report on behalf of the USPSTF.
“Evidence on the effect of screening and early detection of mild to moderate dementia on decision-making, planning, or other important patient outcomes is a critical gap in the evidence,” she added. Other research needs include further study of the harms of screening, new interventions that address the changing needs of patients and families, and interventions that affect the long-term clinical direction of mild to moderate dementia.
In its review, USPSTF evaluated 55 studies of instruments that screen for cognitive impairment, of which 46 provided evidence on the sensitivity of dementia screening and 27 provided evidence on screening for mild cognitive impairment. Tests included various tasks to assess at least one cognitive function, such as memory, attention, language, and visuospatial or executive functioning. USPSTF examined studies that used the Mini-Mental State Examination (MMSE), Clock Drawing Test, verbal fluency tests, Informant Questionnaire on Cognitive Decline in the Elderly, Memory Impairment Screen, Mini-Cog Test, Abbreviated Mental Test, and Short Portable Mental Status Questionnaire.
The MMSE was the most evaluated screening tool, with 25 published studies. The mean age of participants ranged from 69 to 95 years, and the mean prevalence of dementia ranged from 1.2% to 38%. The pooled sensitivity from 14 studies for the most commonly reported cut points was 88.3%, and specificity was 86.2%.
Other screening tools that were evaluated “were studied in far fewer studies (four to seven studies each), had limited reproducibility in primary care–relevant populations, and had unknown optimum cut points,” said Dr. Moyer, Adjunct Professor of Pediatrics at Baylor College of Medicine in Houston.
In addition, no trials studied the “direct effect of screening” by comparing screened and unscreened patients and reporting important clinical and decision-making outcomes, said the report’s authors. Nor did any studies report on direct or indirect harms from false positive or false negative screening results, psychologic harms, unnecessary diagnostic testing, or labeling.
Although this report differs from the 2003 recommendation because it considers screening and treatment for mild cognitive impairment in addition to dementia, and it includes additional information about the test performance of screening instruments, “the overall evidence is insufficient to make a recommendation on screening,” said Dr. Moyer.
—Madhu Rajaraman