Impact of intensive care unit organ failures on mortality during the five years after a critical illness.

Abstract

The relationship between organ failure during critical illness and long-term survival is uncertain, especially among intensive care unit (ICU) survivors. To describe the relationship between individual organ failures, total organ failure burden, and mortality during the 5 years after an episode of critical illness. We studied a cohort of sequential admissions to 10 Scottish ICUs (n = 872). Logistic regression was used to explore independent associations between organ failures and mortality over a 5-year time horizon, adjusting for potential confounders. Daily Sequential Organ Failure Assessment scores described organ dysfunction during ICU stay. The sum of the worst scores at any time point during the ICU stay for each organ system except neurological dysfunction was used to calculate total organ failure burden. Mortality was obtained from the national death register. Five-year mortality was 58.2%; 34.4% of deaths occurred within 28 days. In adjusted analyses, cardiovascular (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.8-3.7), liver (OR, 2.3; 95% CI, 1.1-5.0), and respiratory failure (OR, 2.1; 95% CI, 1.3-3.5) were independently associated with 5-year mortality. Organ failure burden was strongly associated with mortality; 81% of patients in the highest tertile died during follow-up (OR, 6.3 relative to lowest tertile; P < 0.001). Patients surviving more than 12 months post-ICU were still more likely to subsequently die if they experienced greater organ failure burden in the ICU (OR, 2.4; P = 0.02, highest vs. lowest tertile). Cardiovascular, respiratory, and liver failures during critical illness strongly predict subsequent 5-year survival. Acute organ failure burden is associated with long-term mortality even among patients who survive up to 1 year after ICU admission.