Functional Effects of Intervening Illnesses and Injuries After Critical Illness in Older Persons

Objectives: Intervening illnesses and injuries have pronounced deleterious effects on functional status in older persons, but have not been carefully evaluated after critical illness. We set out to evaluate the functional effects of intervening illnesses and injuries in the year after critical illness.

Design: Prospective longitudinal study of 754 nondisabled community-living persons, 70 years old or older.

Setting: Greater New Haven, CT, from March 1998 to December 2018.

Patients: The analytic sample included 250 ICU admissions from 209 community-living participants who were discharged from the hospital.

Interventions: None.

Measurements and main results: Functional status (13 activities) and exposure to intervening illnesses and injuries leading to hospitalization, emergency department visit, or restricted activity were assessed each month. Comprehensive assessments (for covariates) were completed every 18 months. In the year after critical illness, recovery of premorbid function was observed for 169 of the ICU admissions (67.6%), and the mean (sd) number of episodes of functional decline (from 1 mo to the next) was 2.2 (1.6). The adjusted hazard ratios (95% CI) for recovery were 0.18 (0.09-0.39), 0.46 (0.17-1.26), and 0.75 (0.48-1.18) for intervening hospitalizations, emergency department visits, and restricted activity, respectively. For functional decline, the corresponding odds ratios (95% CI) were 2.06 (1.56-2.73), 1.78 (1.12-2.83), and 1.25 (0.92-1.69). The effect sizes for hospitalization and emergency department visit were larger than those for any of the covariates.

Conclusions: In the year after critical illness, intervening illnesses and injuries leading to hospitalization and emergency department visit are strongly associated with adverse functional outcomes, with effect sizes larger than those of traditional risk factors. To improve functional outcomes, more aggressive efforts will be needed to prevent and manage intervening illnesses and injuries after critical illness.