Trends in observation stays for Medicare beneficiaries with and without Alzheimer's disease and related dementias.

Background: There has been a marked rise in the use of observation care for Medicare beneficiaries visiting the emergency department (ED) in recent years. Whether trends in observation use differ for people with Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) is unknown.

Methods: Using a national 20% sample of Medicare beneficiaries ages 68+ from 2012 to 2018, we compared trends in ED visits and observation stays by AD/ADRD status for beneficiaries visiting the ED. We then examined the degree to which trends differed by nursing home (NH) residency status, assigning beneficiaries to four groups: AD/ADRD residing in NH (AD/ADRD+ NH+), AD/ADRD not residing in NH (AD/ADRD+ NH-), no AD/ADRD residing in NH (AD/ADRD- NH+), and no AD/ADRD not residing in NH (AD/ADRD- NH-).

Results: Of 7,489,780 unique beneficiaries, 18.6% had an AD/ADRD diagnosis. Beneficiaries with AD/ADRD had more than double the number of ED visits per 1000 in all years compared to those without AD/ADRD and saw a faster adjusted increase over time (+26.7 vs. +8.2 visits/year; p < 0.001 for interaction). The annual increase in the adjusted proportion of ED visits ending in observation was also greater among people with AD/ADRD (+0.78%/year, 95% CI 0.77-0.80%) compared to those without AD/ADRD (+0.63%/year, 95% CI 0.59-0.66%; p < 0.001 for interaction). Observation utilization was greatest for the AD/ADRD+ NH+ population and lowest for the AD/ADRD- NH- population, but the AD/ADRD+ NH- group saw the greatest increase in observation stays over time (+15.4 stays per 1000 people per year, 95% CI 15.0-15.7).

Conclusions: Medicare beneficiaries with AD/ADRD have seen a disproportionate increase in observation utilization in recent years, driven by both an increase in ED visits and an increase in the proportion of ED visits ending in observation.