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Article History

Received: 8 January 2026

Accepted: 19 May 2026

First Online: 25 May 2026

Declarations

:

: The authors declare no competing interests.

: This study was conducted using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database, a publicly available critical care database. Access to MIMIC-IV was granted after completion of the Collaborative Institutional Training Initiative (CITI) “Data or Specimens Only Research” course (Record ID: 64600981). As MIMIC-IV contains de-identified data in compliance with the Health Insurance Portability and Accountability Act (HIPAA), the requirement for individual patient consent was waived. This study was conducted in accordance with the Declaration of Helsinki. The study was initiated in January 2025 with a formal application to the Non-Interventional Clinical Research Ethics Committee of Ankara Yıldırım Beyazıt University Yenimahalle Training and Research Hospital. For the initial descriptive secondary-analysis phase of the de-identified MIMIC-IV dataset, the committee issued a formal letter (Decision No. E-2025-04, January 2025) confirming that ethics-committee approval was not required. Retrospective data were subsequently extracted and assembled under this letter and under the PhysioNet Data Use Agreement, with no direct patient contact at any stage. When the analytical plan was expanded to include the post-hoc advanced analyses reported here (inflammatory-index computation, multivariable and Firth-penalised regression, LASSO variable selection, and composite severe-adverse-outcome analysis), a second, dedicated application was filed with the same ethics committee in November 2025 to authorise these post-hoc analyses. Approval was granted on 27 November 2025 (Decision No. E-2025-36), and all pre-specified post-hoc analyses reported in this manuscript were conducted on the retrospective de-identified dataset under the authority of that approval prior to manuscript submission, consistent with the policies of the Massachusetts Institute of Technology and Beth Israel Deaconess Medical Center for de-identified data.