POLARIS

Rationale & methods

Prospective validation
in routine care

POLARIS evaluates the prognostic value, decision relevance and transportability of clinically assigned inflammatory phenotypes.

Study design

POLARIS is a prospective, international observational study in adult intensive care units. The protocol follows the 2023 Global Definition of ARDS, including eligible patients receiving non-invasive support. Routine clinical, laboratory and ventilatory data support phenotype assignment at baseline and repeated assessment.

The primary outcome is 28-day mortality. Secondary objectives include transportability across countries and care settings, and heterogeneity in associations with early intravenous corticosteroids within a prespecified causal analysis.

Biology and clinical classification

AI-CLARITY estimates inflammatory phenotypes from routine measurements. This clinical estimate is a surrogate for the biological phenotype. Prognostic separation does not establish biological agreement or demonstrate that phenotype-guided treatment improves outcomes. Biomarker agreement is an exploratory objective where measurements are available.

AI-CLARITY

AI-CLARITY uses the original, frozen XGBoost model and 18 routinely available clinical and laboratory variables. XGBoost combines decision trees to estimate the probability of an inflammatory phenotype. The model has been validated in independent cohorts.

Scientific sources

  1. Pensier J, Fosset M, Paschold BS, von Wedel D, Redaelli S, Braeuer BLP, et al. Temporal stability of phenotypes of acute respiratory distress syndrome: clinical implications for early corticosteroid therapy and mortality. Intensive Care Med. 2025;51(10):1784-96. doi: 10.1007/s00134-025-08089-4.
  2. van Amstel RBE, Reilly JP, Bos LDJ. Open-source clinical classifiers for ARDS: democratizing precision or diluting biology? Intensive Care Med. 2025;51(11):2123-5. doi: 10.1007/s00134-025-08169-5.
  3. Pensier J, Fosset M, Paschold BS, von Wedel D, Sharif M, Braeuer BLP, et al. Effects of inflammatory phenotypes in acute respiratory distress syndrome on mortality and partitioning of lung and chest wall mechanics in patients in the USA and Canada: a retrospective cohort study. Lancet Respir Med. 2026;14(7):609-19. doi: 10.1016/S2213-2600(26)00045-7.
  4. Matthay MA, Arabi Y, Arroliga AC, Bernard G, Bersten AD, Brochard LJ, et al. A new global definition of acute respiratory distress syndrome. Am J Respir Crit Care Med. 2024;209(1):37-47. doi: 10.1164/rccm.202303-0558WS.

For questions about study participation and site activation, contact the coordinating team.