This is a medical research study that uses information from past patient hospital records. It focuses on three serious conditions that often affect critically ill patients: sepsis (a life-threatening body-wide infection), ARDS (a severe lung injury that makes breathing very difficult), and acute kidney injury (sudden loss of kidney function). The goal is to better understand which patients in the ICU are at highest risk of developing these conditions or getting worse. Researchers will look at de-identified information from medical records of patients treated in the ICU . The study will use computer analysis to find patterns in the data that may help doctors predict these risks earlier. No new treatments are being tested, and no patients will be contacted or recruited for this study. All data used is anonymous to protect patient privacy.

Inclusion Criteria:

• Adult patients (age ≥ 18 years).
• Admitted to the ICU with a length of stay ≥ 24 hours.
• Availability of key clinical variables within the first 24 hours of ICU admission (e.g., vital signs, laboratory results, admission diagnosis).

Exclusion Criteria:

• Patients with incomplete or missing key data for model variables (e.g., missing baseline creatinine, or missing Sequential Organ Failure Assessment (SOFA) score components).
• Patients admitted for palliative care or comfort measures only upon ICU admission.
• Readmissions during the same hospitalization (only the first ICU admission will be included).

A retrospective cohort of critically ill adult patients admitted to the intensive care unit (ICU). The study population will be derived from de-identified electronic health records.

The individual participant data (IPD) underlying the results of this study cannot be made publicly available due to restrictions imposed by Chinese data protection laws and regulations, as well as the data use agreements with the source hospital(s). The data contain sensitive clinical information, and public sharing would compromise patient privacy and confidentiality. Aggregated data or analysis results will be made available in the published manuscript. Requests for specific analyses can be directed to the corresponding author.