(1182) Longitudinal Oxygenation Subphenotypes in ARDS: A Multi-Database Study

Introduction: Identifying longitudinal subphenotypes of Acute Respiratory Distress Syndrome (ARDS) is important for achieving precision in critical care management. Currently, bedside dynamic trajectory subphenotypes for ARDS are lacking. This study aimed to identify and validate ARDS subphenotypes using PaO2/FiO2 (P/F) ratio trajectories and investigate their association with clinical outcomes and treatment responses.

Methods: This study used the Chinese Database in ARDS (CHARDS), data from three randomized controlled trials for ARDS (FACTT, SAILS, and ALVEOLI trials), and the MIMIC-IV Database. Group-based trajectory modeling was applied to P/F changes from the day of ARDS diagnosis to day 7 to determine distinct subphenotypes. Clinical characteristics and outcomes were compared along with treatment responses among the identified subphenotypes.

Results: A total of 814 and 2505 ARDS patients were included in the training (CHARDS) and validation cohorts (FACTT, SAILS, ALVEOLI, and MIMIC-IV), respectively. Three subphenotypes were identified. Group 1 was characterized by the severest condition with a persistently low P/F over time, a higher number of complications and organ failures, and the highest 60-day mortality (72.86%). Group 2 exhibited moderate severity, with P/F gradually increasing over time and intermediate 60-day mortality (32.84%). Group 3 presented with the mildest disease manifestations, with rapidly improving P/F over time, fewer abnormal laboratory values, less organ failure, and the lowest 60-day mortality rate (17.86%). Similar subphenotypes were observed in the validation cohorts. Significant heterogeneity of treatment effects were observed between the subphenotypes and ECMO strategy implementation in the CHARDS and MIMIC-IV cohorts and the subphenotypes and high or low PEEP treatment strategies in the CHARDS and ALVEOLI trials.

Conclusions: We identified three bedside longitudinal trajectory subphenotypes of ARDS that may exhibit differential responses to ECMO and PEEP.