Predicting ARDS mortality based on a simple clinical score

From a paper in Critical Care Medicine:

Objectives: Although there is general agreement on the characteristic features of the acute respiratory distress syndrome, we lack a scoring system that predicts acute respiratory distress syndrome outcome with high probability. Our objective was to develop an outcome score that clinicians could easily calculate at the bedside to predict the risk of death of acute respiratory distress syndrome patients 24 hours after diagnosis.

Design: A prospective, multicenter, observational, descriptive, and validation study.

Setting: A network of multidisciplinary ICUs.

Patients: Six-hundred patients meeting Berlin criteria for moderate and severe acute respiratory distress syndrome enrolled in two independent cohorts treated with lung-protective ventilation.

Interventions: None.

Measurements and Main Results: Using individual demographic, pulmonary, and systemic data at 24 hours after acute respiratory distress syndrome diagnosis, we derived our prediction score in 300 acute respiratory distress syndrome patients based on stratification of variable values into tertiles, and validated in an independent cohort of 300 acute respiratory distress syndrome patients. Primary outcome was in-hospital mortality. We found that a 9-point score based on patient’s age, PaO2/FIO2 ratio, and plateau pressure at 24 hours after acute respiratory distress syndrome diagnosis was associated with death. Patients with a score greater than 7 had a mortality of 83.3% (relative risk, 5.7; 95% CI, 3.0–11.0), whereas patients with scores less than 5 had a mortality of 14.5% (p less than 0.0000001). We confirmed the predictive validity of the score in a validation cohort.

The score is explained in this piece in ACP Hospitalist Weekly:

The score the researchers chose had a minimum of 3 points and a maximum of 9, based on 3 variables: age in years (less than 47, 47 to 66, greater than 66), PaO2/FIO2 in mm Hg (Greater than 158, 105 to 158, less than 105), and plateau pressure in cm H2O (less than 27, 27 to 30, greater than 30). Seven other variables were evaluated for potential inclusion in the score but were not selected. Patients with a score greater than 7 were found to have an inpatient mortality rate of 83.3%, compared to 14.5% in patients with a score below 5, the study found.

Note that the score is only to be applied to the Berlin categories of moderate and severe ARDS.