Late-onset moderate to severe acute respiratory distress syndrome is associated with shorter survival and higher mortality: a two-stage association study.

Abstract

To evaluate the association between acute respiratory distress syndrome (ARDS) onset time and prognosis. Patients with moderate to severe ARDS (N=876) were randomly assigned into derivation (N=520) and validation (N=356) datasets. Both 28-day and 60-day survival times after ARDS onset were analyzed. A data-driven cutoff point between early- and late-onset ARDS was determined on the basis of mortality risk effects of onset times. We estimated the hazard ratio (HR) and odds ratio (OR) of late-onset ARDS using a multivariate Cox proportional hazards model of survival time and a multivariate logistic regression model of mortality rate, respectively. Late-onset ARDS, defined as onset over 48h after intensive care unit (ICU) admission (N=273, 31%), was associated with shorter 28-day survival time: HR=2.24, 95% CI 1.48-3.39, P=1.24×10-4 (derivation); HR=2.16, 95% CI 1.33-3.51, P=1.95×10-3 (validation); and HR=2.00, 95% CI 1.47-2.72, P=1.10×10-5 (combined dataset). Late-onset ARDS was also associated with shorter 60-day survival time: HR=1.70, 95% CI 1.16-2.48, P=6.62×10-3 (derivation); HR=1.78, 95% CI 1.15-2.75, P=9.80×10-3 (validation); and HR=1.59, 95% CI 1.20-2.10, P=1.22×10-3 (combined dataset). Meanwhile, late-onset ARDS was associated with higher 28-day mortality rate (OR=1.46, 95% CI 1.04-2.06, P=0.0305) and 60-day mortality rate (OR=1.44, 95% CI 1.03-2.02, P=0.0313). Late-onset moderate to severe ARDS patients had both shorter survival time and higher mortality rate in 28-day and 60-day observations.