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

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 48 h 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 x 10(-4) (derivation); HR = 2.16, 95% CI 1.33-3.51, P = 1.95 x 10(-3) (validation); and HR = 2.00, 95% CI 1.47-2.72, P = 1.10 x 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 x 10(-3) (derivation); HR = 1.78, 95% CI 1.15-2.75, P = 9.80 x 10(-3) (validation); and HR = 1.59, 95% CI 1.20-2.10, P = 1.22 x 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.