Long-term mortality of patients discharged from the hospital after successful critical care in the ICU in Korea: a retrospective observational study in a single tertiary care teaching hospital

Abstract

Background: The long-term outcomes of patients discharged from the hospital after successful care in intensive care unit (ICU) are not briskly evaluated in Korea. The aim of this study was to assess long-term mortality of patients treated in the ICU and discharged alive from the hospital and to identify predictive factors of mortality.

Methods: In 3,679 adult patients discharged alive from the hospital after ICU care between 2006 and 2011, the 1-year mortality rate (primary outcome measure) was investigated. Various factors were entered into multivariate analysis to identify independent factors of 1-year mortality, including sex, age, severity of illness (APACHE II score), mechanical ventilation, malignancy, readmission, type of admission (emergency, elective surgery, and medical), and diagnostic category (trauma and non-trauma).

Results: The 1-year mortality rate was 13.4%. Risk factors that were associated with 1-year mortality included age (hazard ratio: 1.03 [95% CI, 1.02-1.04], P < 0.001), APACHE II score (1.03 [1.01-1.04], P < 0.001), mechanical ventilation (1.96 [1.60-2.41], P < 0.001), malignancy (2.31 [1.82-2.94], P < 0.001), readmission (1.65 [1.31-2.07], P < 0.001), emergency surgery (1.66 [1.18-2.34], P = 0.003), ICU admission due to medical causes (4.66 [3.68-5.91], P < 0.001), and non-traumatic diagnostic category (6.04 [1.50-24.38], P = 0.012).

Conclusions: The 1-year mortality rate was 13.4%. Old age, high APACHE II score, mechanical ventilation, malignancy, readmission, emergency surgery, ICU admission due to medical causes, and non-traumatic diagnostic category except metabolic/endocrinologic category were associated with 1-year mortality.

Keywords: Critical care outcomes; Intensive care unit; Long-term outcomes; Mortality; Risk factors; Survival analysis.

Fig. 1.

Flow diagram of patient screening for this study. The schematic shows the inclusion criteria for patients admitted to the ICU from 2006 to 2011. DNR: do not resuscitation, ICU: intensive care unit.

Fig. 2.

Cox’s regression analysis curves showing 1-year mortality after hospital discharge of the total post-ICU patients and subgroups based on the type of admission. ICU: intensive care unit. ^*Emergency surgical patients have a higher mortality compared with elective surgical patients (P = 0.003). ^†Medical patients have a higher mortality compared with elective surgical patients (P < 0.001).