In-hospital mortality for aspiration pneumonia in a tertiary teaching hospital: A retrospective cohort review from 2008 to 2018

Background Aspiration pneumonia is a preventable condition that has higher rates of recurrence and mortality compared to non-aspiration pneumonia. The primary objective of the study was to examine independent patient factors that are associated with mortality in those requiring acute admission for aspiration pneumonia at a tertiary institution. Secondary goals of the study were to review whether factors such as mechanical ventilation and speech language pathology intervention can impact patient mortality, length of stay (LOS), and costs relating to hospitalization.Methods Patients older than 18 years of age who were admitted with a primary diagnosis of aspiration pneumonia from January 1, 2008 to December 31, 2018 at Unity Health Toronto-St. Michael's hospital in Toronto, Canada, were included in the study. Descriptive analyses were performed on patient characteristics using age as a continuous variable as well as a dichotomous variable with age 65 as a cut-off. Multivariable logistic regression was used to identify independent factors that contributed to in-hospital mortality and Cox proportional-hazard regression was used to identify independent factors that affected LOS.Results A total of 634 patients were included in this study. 134 (21.1%) patients died during hospitalization with an average age of 80.3 +/- 13.4. The in-hospital mortality did not change significantly over the ten-year period (p = 0.718). Patients who died had longer LOS with a median length of 10.5 days (p = 0.012). Age [Odds Ratio (OR) 1.72, 95% Confidence Interval (95% CI) 1.47-2.02, p < 0.05] and invasive mechanical ventilation (OR 2.57, 95% CI 1.54-4.31, p < 0.05) were independent predictors of mortality while female gender was found to be a protective factor (OR 0.60, 95% CI 0.38-0.92, p = 0.02). Elderly patients had five times higher risk of dying during their hospital course when compared to younger patients [Hazard Ratio (HR) 5.25, 95% CI 2.99-9.23, p < 0.05).Conclusion Elderly patients are a high-risk population for developing aspiration pneumonia and are at higher risk of death when hospitalized for this condition. This warrants improved preventative strategies in the community. Further studies involving other institutions and creating a Canada-wide database are required.