A Call to Selective Dementia Screening

April 11, 2018

A new study makes the case for universal screening in patients who appear to be most vulnerable to underdiagnosis.

Nearly 60% of older adults with dementia either have slipped under the radar or are unaware of their diagnosis, according to a study by a team of researchers from Johns Hopkins University in Baltimore, Maryland.1 Persons living with undiagnosed dementia are less likely to be white, more likely to have a lower educational level, and are less likely to visit doctors with a companion who can act as a proxy. They also tend to have less functional impairment than persons who have a dementia diagnosis on record, according to the study. Likewise, among persons with a formal diagnosis, those unaware of it are more likely to have a lower educational level and less functional impairment. They also are more likely to attend doctor visits alone.

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Although an estimated 5.5 million people are living with dementia in the US2[PDF] and although dementia is a major topic of discussion regarding health, aging, and healthcare expenditures, dementia is thought to be underdiagnosed by clinicians and underreported by patients and their caregivers. “Despite increased public awareness of dementia, many patients aren’t diagnosed until a crisis or significant event occurs. Our study highlights groups of older adults who could potentially be diagnosed and supported before a crisis occurs,” explained lead study author Halima Amjad, MD, MPH, Assistant Professor of Medicine in the Division of Geriatric Medicine and Gerontology and the Center for Transformative Geriatric Research at Johns Hopkins.1

The team noted that no studies have examined dementia diagnosis in relation to patient or family awareness of the diagnosis, and very few studies have examined dementia diagnosis or lack thereof in nationally representative populations. The team, thus, conducted a nationally representative study to learn more about the demographic profiles of patients with undiagnosed dementia and those who have received a diagnosis but are unaware of it.

Demographic, social/behavioral, functional, medical, and health care utilization characteristics of older adults with dementia using the National Health and Aging Trends Study (NHATS), a national population-based cohort of Medicare beneficiaries age 65 years and older. Of 8245 NHATS participants, 585 with probable dementia were identified for study inclusion. Of these, 229 did not have a diagnosis on record and 356 did. Of those who did, a third (116) was aware of the diagnosis. Probable dementia was defined by either a self or proxy report of having received a clinical diagnosis of dementia or Alzheimer disease, a score of 2 or greater on the AD-8 Dementia Screening Interview (administered to proxies), and/or a score that was more than 1.5 standard deviations below the mean for 2 or 3 cognitive domains tested in the affected person.

Probable dementia was undiagnosed in 39.5% of the study population. Among those with a diagnosis on record, 19.2% were unaware of their diagnosis.

Compared with persons with a diagnosis, those with undiagnosed dementia were younger, more likely to be male and non-white (especially Hispanic; odds ratio [OR] 2.48); have less than high school education; and attend doctor visits alone. Indeed, persons who attended doctor visits alone had almost twice the odds of being undiagnosed than did persons who had someone to accompany them to doctor visits (OR 1.98). They also were higher functioning, having fewer instrumental activities of daily living (IADL) deficits, and were less likely to present for medical care.

The authors especially stressed that the more functional a person was in relation to IADL, such as in managing finances and medications, the easier it was for him or her to fall under the radar regarding a dementia diagnosis. Higher levels of cognitive functioning in these persons can mask deficits, such as poor insight and memory, when presenting to health care personnel. Although neuropsychiatric symptoms are common in dementia, presence of depression or anxiety did not significantly affect the likelihood of diagnosis or awareness of diagnosis of dementia.

Although guidelines of the US Preventive Services Task Force have found insufficient evidence to support universal screening,3 the Johns Hopkins team1advocated screening for those who appear to be most vulnerable to underdiagnosis: non-white older adults and persons with lower education levels.

References:

1. Amjad H, Roth DL, Sheehan OC, et al. Underdiagnosis of dementia: an observational study of patterns in diagnosis and awareness in US older adults. J Gen Intern Med. 2018 Mar 5. [Epub ahead of print]

2. Alzheimer’s Association. 2017 Alzheimer's Disease Facts and Figures. https://www.alz.org/documents_custom/2017-facts-and-figures.pdf. Accessed April 10, 2018.

3. Moyer VA, U.S. Preventive Services Task Force. Screening for cognitive impairment in older adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;160:791-797.