Background

The “baby boomers” are individuals born in the United States between 1946 and 1964, marked by a substantial rise in birth rates post‐World War II.¹ Baby boomers started turning 65 in 2011, and there were 77 million people older than 65 in 2011, and by 2030, there will be 60 million.¹ Longevity is the result of higher income and education, so it comes as no surprise that socioeconomic inequalities widen the gap of life expectancy.^2,3 Terms such as “elderly” are offensive for some of society with alternative terminology like “older adult” or “geriatric” deemed more acceptable.⁴ Defining the threshold for “older adults” in the late twentieth century often used aged 65 years or older but may vary across regions depending on populations and resources. Multiorganizational guidelines exist to standardize the “geriatricization” of care in the adult emergency department (ED), though these recommendations are primarily consensus‐based rather than research‐based.⁵ Despite the lack of high‐quality supporting evidence, the American College of Emergency Physicians has created Geriatric Emergency Department Guidelines aiming to improve the care seniors receive in the ED. There have been several articles trying to demonstrate the cost‐effectiveness for these efforts.^6–8 Most recently, a study by Hwang et al.⁹ found that patients cared for in a geriatric ED by a transitional care nurse or social work had lower Medicare expenditures at 30 and 60 days after an ED visit.

Older adults often present to the ED with atypical disease manifestations, including pyuria that is usually not a urinary tract infection^10,11 or minor trauma that is potentially life threatening.¹² In addition, unrecognized co‐morbidities like dementia or acute illness like delirium frequently exist, either of which can prolong ED length of stay, admission rates, and preventable readmissions.^13,14 “Geriatric syndromes” include falls,¹⁵ delirium,¹⁶ dementia,¹⁷ frailty,¹⁸ functional decline,¹⁹ and polypharmacy.²⁰ With aging populations and established guidelines, ED physicians will be increasingly expected to identify and initiate management of prevalent geriatric syndromes in coming decades.^21,22

Clinical question

In older ED patients at risk for cognitive dysfunction, what are the diagnostic test characteristics of brief dementia screening tests?

Cognitive dysfunction includes mild cognitive impairment, delirium, and dementia. Approximately 30% of older adult ED patients have an abnormal dementia screening test with a range from 12% to 43%.²³ Emergency physicians miss the majority of dementia (and delirium) presenting to the ED.^24,25 Cognitive dysfunction in older ED patients is associated with accelerated functional decline or short‐term readmissions,¹⁴ falls,²⁶ impaired driving safety,²⁷ lower patient satisfaction,²⁸ and lower caregiver quality of life.²⁹ Alzheimer’s disease is the most common dementia subtype, afflicts 5 million Americans in 2020 and is projected to increase to 14 million by 2050 with an increase in dementia‐related healthcare costs from $305 billion to $1.1 trillion over that period.³⁰ Historically, the Mini–Mental State Examination (MMSE) was used to assess for dementia in research settings, but this instrument is not sufficiently brief for practical use clinically, was not originally derived to diagnose dementia, and has not been formally validated in the ED.^23,31,32 The MMSE is particularly inaccurate in identifying mild cognitive impairment with a sensitivity as low as 18%.³³ In addition, the MMSE has unacceptably high false‐positive rates in poorly educated and lower socioeconomics subgroups.^34,35 Mild cognitive impairment is characterized by memory or language problems that do not interfere with daily activities, but which can be detected by certain screening tests.³⁶ The prevalence and optimal screening instruments for mild cognitive impairment in the ED have not yet been identified.²³

A recent ED‐based diagnostic meta‐analysis identified seven dementia screening instruments with diagnostic accuracy summarized in Table 57.1.²³ The Short Blessed Test (SBT) and Brief Alzheimer’s Screen (BAS) also identified all cases of delirium.³⁷ Based on two European ED studies, the Abbreviated Mental Test (AMT‐4) (Table 57.2) demonstrates the highest positive likelihood ratio to increase the probability of dementia in older adults.^38,39 Although the BAS had the lowest negative likelihood ratio to decrease the probability of dementia, it is too complex for incorporation into routine ED screening. The Ottawa 3DY (Table 57.3) balances brevity and simplicity with a lower negative likelihood ratio, although the confidence intervals across three studies are wide.^37,40,41 Notably, highly educated patients can create false‐negative ED dementia screening results, but the caregiver‐administered AD8 (Table 57.4) does not rely upon objective patient evaluation and may be preferable in that population.²³ The testing threshold was discussed in Chapter 1 and is estimated to benefit patients with a pretest probability of 15–43%, which is within the range that the average older ED patient presents.²³