Impact of Clinical Frailty Scale on Morbidity and Mortality in Older Adults Diagnosed With Pneumonia in the Emergency Department: A Prospective Observational Cohort Study

Pneumonia represents a major cause of hospitalization, intensive care admission, and mortality in older adults worldwide. Aging is associated with multimorbidity and immunosenescence, increasing vulnerability to infection and poor outcomes. Current risk stratification tools used in emergency departments, including PSI and CURB-65, are designed to estimate short-term mortality based on acute clinical variables. However, these tools may not fully reflect functional reserve and biological age.

Frailty is characterized by decreased physiological reserve and increased susceptibility to adverse outcomes. The Clinical Frailty Scale (CFS), based on the deficit accumulation model, provides a rapid bedside assessment of global functional status using a 9-point scale. Emerging evidence suggests that frailty is an independent predictor of mortality and morbidity in older emergency department populations.

This single-center prospective observational cohort study will be conducted in a tertiary university hospital emergency department. Patients aged ≥65 years with a clinical and radiological diagnosis of pneumonia will be enrolled consecutively. Demographic data, comorbidities, vital signs, and PSI scores will be recorded at presentation. Frailty will be assessed using the Clinical Frailty Scale at the bedside.

The primary outcomes are in-hospital mortality and 30-day mortality. Secondary outcomes include intensive care unit admission and need for mechanical ventilation. Statistical analysis will evaluate whether CFS independently predicts outcomes and whether adding frailty assessment to existing pneumonia severity scores improves prognostic performance.