Table 2

Multivariable predictors of returning to work within 5 years of ARDS*

CharacteristicHR (95% CI)p Value
Model 1: baseline variables
Age at ARDS diagnosis, per year ≤40 years0.99 (0.95 to 1.04)0.79
Age at ARDS diagnosis, per year >40 years0.97 (0.93 to 1.02)0.28
Charlson Comorbidity Index, per point0.75 (0.56 to 0.99)0.05
Functional Comorbidity Index, per point0.93 (0.72 to 1.20)0.55
Model 2: ICU and discharge variables
Mechanical ventilation, per day ≤5 days0.66 (0.54 to 0.81)<0.001
Mechanical ventilation, per day >5 days1.02 (0.99 to 1.05)0.22
Discharge to rehabilitation or other healthcare facility0.41 (0.21 to 0.78)0.01
Model 3: final multivariable model
Charlson Comorbidity Index, per point0.77 (0.59 to 0.99)0.04
Mechanical ventilation, per day ≤5 days0.67 (0.55 to 0.82)<0.001
Mechanical ventilation, per day >5 days1.02 (0.99 to 1.05)0.20
Discharge to rehabilitation or other healthcare facility0.49 (0.26 to 0.93)0.03
  • *HR calculated using Fine and Grey regression models, with a HR <1 indicating a slower time to return to work. To build multivariable models, covariates having univariable associations at p≤0.20 with the primary outcome (online supplementary eTable 1) were included in multivariable models. To prevent overfitting of the multivariable regression models, submodels were created, involving baseline patient variables (model 1) and ICU and hospital discharge variables (model 2). In these sub-models, multicollinearity was observed between APACHE II score, mean daily SOFA score, duration of mechanical ventilation and hospital LOS and addressed by omitting the non-significant variables (APACHE II, SOFA and hospital LOS) from the final model. Remaining variables from models 1 and 2 with an association of p≤0.20 were subsequently included in the final multivariable model (model 3).

  • APACHE, Acute Physiology and Chronic Health Evaluation; ARDS, acute respiratory distress syndrome; LOS, length of stay; SOFA, Sequential Organ Failure Assessment.