Prognostic performance of the Age, PaO₂/FiO₂ Ratio, and Plateau Pressure Score (APPS) for mortality in patients with COVID-19-associated acute respiratory distress syndrome admitted to an intensive care unit

Background: A predictive scoring system used in patients with acute respiratory distress syndrome (ARDS) known as Age, PaO₂/FiO₂, Plateau Pressure Score (APPS) has been externally validated to predict mortality in Asian and Caucasian populations. Its performance in Latin American and COVID-19 patients still needs to be done. Objective: To assess the association between APPS and mortality, as well as APPS performance in predicting mortality within 28 days of intensive care unit (ICU) admission in patients with ARDS due to COVID-19. Design: Analytical observational retrospective cohort study. Methods: We conducted a retrospective cohort study in patients diagnosed with ARDS according to the Berlin criteria who were admitted to the ICU. We evaluated the prognostic performance of APPS using the area under the receiver operating characteristic curve (AUC-ROC), and association with mortality was measured using the Cox proportional hazards regression models. Results: A total of 271 patients were analyzed. The AUC for 28-day mortality was 0.78 (95% CI: 0.73–0.84). In the Cox proportional hazards model, after adjusting for sex and categorized Charlson Comorbidity Index, it was found that grade 2 APPS (aHR: 3.67, 95% CI: 2.14–6.30, p < 0.001) and grade 3 APPS (aHR: 7.95, 95% CI: 3.72–17.02, p < 0.001) were associated with a higher hazard of 28-day mortality. Conclusion: The APPS scoring system has a good prognostic performance for mortality in patients diagnosed with COVID-19-induced ARDS.