Trends in Geriatric Conditions Among Older Adults Admitted to US ICUs Between 1998 and 2015

BACKGROUND: Older adults are increasingly admitted to the ICU, and those with disabilities, dementia, frailty, and multimorbidity are vulnerable to adverse outcomes. Little is known about how pre-existing geriatric conditions have changed over time. RESEARCH QUESTION: How have changes in disability, dementia, frailty, and multimorbidity in older adults admitted to the ICU changed from 1998 through 2015? STUDY DESIGN AND METHODS: Medicare-linked Health and Retirement Survey (HRS) data identifying patients 65 years of age and older admitted to an ICU between 1998 and 2015. ICU admission was the unit of analysis. Year of ICUadmission was the exposure. Disability, dementia, frailty, and multimorbidity were identified based on responses to HRS surveys before ICU admission. Disability represented the need for assistance with >= 1 activity of daily living. Dementia used cognitive and functionalmeasures. Frailty included deficits in >= 2 domains (physical, nutritive, cognitive, or sensory function). Multimorbidity represented >= 3 self-reported chronic diseases. Time trends in geriatric conditions weremodeled as a function of year of ICUadmission and were adjusted for age, sex, race or ethnicity, and proxy interview status. RESULTS: Across 6,084 ICU patients, age at admission increased from 77.6 years (95% CI, 76.77-8.4 years) in 1998 to 78.7 years (95% CI, 77.5-79.8 years) in 2015 (P<.001 for trend). The adjusted proportion of ICU admissions with pre-existing disability rose from 15.5% (95% CI, 12.1%-18.8%) in 1998 to 24.0%(95% CI, 18.5%-29.6%) in 2015 (P = .001). Rates of dementia did not change significantly (P = .21). Frailty increased from36.6%(95% CI, 30.9%-42.3%) in 1998 to 45.0%(95% CI, 39.7%-50.2%) in 2015 (P = .04); multimorbidity rose from 54.4%(95% CI, 49.2%59.7%) in 1998 to 71.8% (95% CI, 66.3%-77.2%) in 2015 (P<.001). INTERPRETATION: Rates of pre-existing disability, frailty, and multimorbidity in older adults admitted to ICUs increased over time. Geriatric principles need to be deeply integrated into the ICU setting.