Pharyngeal Residue Is Independently Associated With Mortality and Aspiration Events in Patients Undergoing Swallowing Assessment: A Retrospective Cohort Study.

BACKGROUND: The prognostic significance of pharyngeal residue during routine swallowing assessment remains unclear in older adults at regional hospitals. METHODS: We conducted a single-center retrospective cohort study of 107 consecutive patients (median age 87 years) undergoing swallowing assessment at a regional hospital in Japan (January 2021-December 2024; follow-up until June 2025). The primary outcome was all-cause mortality, and the secondary outcome was aspiration events. Time-to-event analyses used Kaplan-Meier methods, multivariable Cox proportional hazards models, and Fine-Gray subdistribution hazard models to account for the competing risk of death. RESULTS: During a median follow-up of 72 days (IQR 36-156), 72 deaths and 63 aspiration events occurred. Pharyngeal residue was independently associated with aspiration events (HR 3.26; 95% CI 1.70-6.26; p < 0.001) and all-cause mortality (HR 2.65; 95% CI 1.38-5.10; p = 0.003). These findings were consistent in sensitivity analyses excluding antipsychotic use and in Fine-Gray competing risks analysis (SHR 2.76; 95% CI 1.51-5.04; p = 0.001). Dementia was also independently associated with mortality (HR 1.83; 95% CI 1.02-3.29; p = 0.044). CONCLUSIONS: Pharyngeal residue was independently associated with all-cause mortality and aspiration events, supporting its utility as a simple prognostic marker for risk stratification in older adults with suspected dysphagia.