Study objectives: Patients requiring prolonged admission to the ICU consume significant health-care resources and have a high rate of in-hospital death. The long-term mortality outcome of these patients has not been well defined in a nonselected cohort. The objective of this study was to describe the occurrence and factors predictive of prolonged ICU stay at admission, and to define the long-term (>/= 1 year) mortality outcome.
Design: Population-based cohort.
Setting: All adult multisystem and cardiovascular surgical ICUs in the Calgary Health Region (CHR) from July 1, 1999, to March 31, 2002.
Patients: Adult (>/= 18 years old) residents of the CHR admitted to regional ICUs.
Interventions: None.
Measurements and results: During the study, 4,845 patients had a median length of stay of 2 days (interquartile range, 1 to 4 days); 2,115 patients (44%) were admitted for < 2 days, 1,496 patients (31%) were admitted for 2 to 3 days; 1,018 patients (21%) were admitted from 4 to 13 days; and 216 patients (4%) had a prolonged (>/= 14 day) admission to the ICU. A higher severity of illness, the presence of shock, and bloodstream infection were independently associated with a prolonged ICU admission, and cardiovascular surgery was associated with a lower risk. Patients with prolonged ICU admissions were nearly twice as likely to die as patients with shorter ICU admissions: 53 of 216 patients (25%) vs 584 of 4,629 patients (13%) [p = 0.0001]. Among the 3,924 survivors to hospital discharge, the rates of mortality during the year following ICU admission were as follows: 59 deaths in 1,758 patients (3%) admitted < 2 days, 74 deaths in 1,267 patients (6%) with 2- to 3-day admissions, 78 deaths in 766 patients (10%) with 4- to 13-day admissions, and 10 deaths in 133 patients (8%) with admissions >/= 14 days.
Conclusions: One in 25 critically ill patients will have prolonged ICU admission and higher ICU-related mortality. However, survivors of prolonged ICU admission have good long-term mortality outcome after acute illness.