Critical Care: Original Research

The ARDS, Pneumonia, and Sepsis Consortium: Rationale, Design, and Feasibility of a National Platform for Phenotyping Critical Illness Syndromes

Wesley H. Self, Carolyn S. Calfee, Samuel M. Brown, et al

Chest 2026 Available online 13 July 2026

https://doi.org/10.1016/j.chest.2026.05.053

Background

To enhance biological understanding of ARDS, pneumonia, and sepsis and to accelerate therapeutic development in these areas, the National Institutes of Health developed the ARDS, Pneumonia, and Sepsis (APS) Consortium.

Research Question

Is the APS Consortium study rapidly generating data and biospecimens from a large cohort of critically ill adults with ARDS, pneumonia, and sepsis that will facilitate phenotyping of these syndromes?

Study Design and Methods

The APS Consortium Phenotyping Study is a multicenter, longitudinal, prospective, observational cohort study aimed at enrolling 4,000 critically ill adults with ARDS, pneumonia, sepsis, or a combination thereof over 4 years. Data and biospecimens are collected to characterize many aspects of each participant’s chronic health, acute illness, and long-term recovery to facilitate phenotyping, that is, subclassifying ARDS, pneumonia, and sepsis into precise biologically based subsets with shared pathophysiologic characteristics. Feasibility of the study was assessed by evaluating the first 1,000 participants in terms of recruitment pace, participant characteristics, biospecimen collection, and proportion with confirmed ARDS, pneumonia, and sepsis based on expert adjudication.

Results

The first 1,000 participants were recruited ahead of schedule in < 13 months. Median age was 64 years, 75% received vasopressors, 50% received invasive mechanical ventilation, and 25% died in the hospital within 4 weeks of enrollment. Biospecimen collection rates were high, with 99% of participants with blood samples, 98% with upper respiratory swabs, 37% with lower respiratory samples, 80% with urine samples, and 65% with gastrointestinal samples. Expert adjudication resulted in 40% classified with ARDS, 52% classified with pneumonia, and 89% classified with sepsis.

Interpretation

The APS Consortium Phenotyping Study is producing a cohort of critically ill adults with ARDS, pneumonia, and sepsis with high severity of disease and a rich set of data and biospecimens. The study will continue to full enrollment of 4,000 participants.

Clinical Trial Registration

ClinicalTrials.gov; No.: NCT06521502; URL: www.clinicaltrials.gov.