Praxis Medical Insights

Est. 2024 • Clinical Guidelines Distilled

Made possible by volunteer editors from the University of Calgary & University of Alberta

Last Updated: 11/9/2025

Sepsis Subphenotyping in ICU Patients

Introduction to Subphenotyping Approaches

  • Machine learning models have identified four distinct sepsis subphenotypes using more than 25 routinely measured clinical parameters available in standard electronic health data, according to the American Thoracic Society, 1, 2
  • These parameters include vital signs, laboratory values, organ dysfunction scores, and demographic data that are universally available, as recommended by the American College of Chest Physicians, 1
  • This approach requires no specialized biomarkers and can be implemented globally, as suggested by the American Journal of Respiratory and Critical Care Medicine, 1

Practical Clinical Parameter-Based Approaches

  • For ARDS patients, validated 3-4 variable classifiers using clinical data and plasma inflammatory markers (excluding ferritin) can reliably identify subphenotypes with differential mortality and treatment responses, according to the American Thoracic Society, 2, 3
  • The Sequential Organ Failure Assessment (SOFA) score quantifies organ dysfunction severity and serves as a prognostic indicator, as stated by the Society of Critical Care Medicine, 5
  • Number of acquired organ system failures is the most important prognostic indicator for ICU patients, as reported by the American College of Chest Physicians, 5

Organ Dysfunction Scoring Systems

  • Respiratory system compliance in ARDS patients identifies subgroups with differential treatment responses to low tidal volume ventilation, according to the American Thoracic Society, 2
  • Physiologic measurements are readily identifiable using routine clinical data without specialized biomarkers, as suggested by the American Journal of Respiratory and Critical Care Medicine, 4

Important Caveats

  • Subphenotyping approaches must be readily measurable with acceptable operating characteristics to allow global implementation, as recommended by the World Health Organization, 4, 6
  • Clinical severity criteria alone achieve prognostic enrichment but generally fail to enrich for treatment response, according to the American College of Chest Physicians, 1, 3
  • Integration of clinical, biological, and physiologic data provides more robust subphenotyping than single modalities, as stated by the American Thoracic Society, 7