Association of ICU Admission Time, Age Stratification, and Clinical Frailty Scale With 30-Day Mortality in Geriatric Oncology Patients

Geriatric oncology patients admitted from the emergency department to the intensive care unit (ICU) represent a particularly vulnerable population with a high risk of mortality due to advanced age, malignancy-related immunosuppression, multiple comorbidities, and reduced physiological reserve. Limited ICU bed capacity and the increasing burden of critically ill patients have made appropriate triage and timely ICU admission increasingly important in this patient group.

Recent studies have demonstrated that delays in ICU admission from the emergency department (boarding time) are significantly associated with increased 30-day mortality. In particular, delays ranging from 5 to 12 hours have been shown to exhibit a dose-response relationship, with mortality risk increasing in parallel with prolonged waiting times. Similarly, studies conducted in critically ill oncology patients have identified delayed ICU admission and ICU triage decisions made during off-hours as independent predictors of 30-day mortality. These findings suggest that multidisciplinary ICU triage during regular working hours and a lower threshold for ICU admission in critically ill oncology patients may improve clinical outcomes.

Furthermore, prolonged emergency department boarding before ICU admission has consistently been associated with adverse clinical outcomes and increased mortality among critically ill patients. Therefore, minimizing delays in ICU admission may represent an important strategy for improving prognosis in this high-risk population.

Despite these observations, there remains a paucity of data evaluating the independent effects of boarding time, Clinical Frailty Scale (CFS) score, and age on 30-day mortality in geriatric oncology patients. Therefore, the primary objective of this study is to investigate the independent associations of emergency department boarding time, CFS score, and age with 30-day mortality among oncology patients aged 65 years and older admitted from the emergency department to the Anesthesiology and Reanimation Intensive Care Unit (ARICU).

Patients will be stratified into three age groups: 65-74 years, 75-84 years, and ≥85 years. This classification is expected to provide a more detailed assessment of the impact of age-related differences in biological and physiological reserve, as well as tolerance to oncological treatments, on clinical outcomes.

The relationships between boarding time, CFS score, age, and 30-day mortality will be analyzed using multivariable statistical models adjusted for potential confounding variables, including disease severity indices such as the Sequential Organ Failure Assessment (SOFA) score and/or Acute Physiology and Chronic Health Evaluation II (APACHE II) score, cancer type and stage, comorbidity burden, and organ support therapies.

The findings of this study are expected to contribute to the optimization of ICU admission processes, improve risk stratification, and enhance understanding of the prognostic importance of early intensive care intervention in geriatric oncology patients. In addition, the results may provide a scientific basis for the development of evidence-based ICU admission and patient selection criteria for this high-risk population.

Inclusion criteria

• Age ≥ 65 years
• Diagnosis of solid or hematologic malignancy
• Admission from the Emergency Department to the Anesthesiology and Reanimation Intensive Care Unit
• ICU admission between January 1, 2026 and July 1, 2026

Exclusion criteria

• Age < 65 years
• Missing data regarding boarding time, Clinical Frailty Scale score, or 30-day mortality
• Readmission to the ICU during the same hospitalization
• Patients transferred from hospital wards or other ICUs