Study population and patient settings
This study was approved by the Institutional Review Board of Nagano Prefectural Shinshu Medical Center (approval no: ShinshurinriR3-2, Suzaka City, Japan). As this was a retrospective analysis, informed consent was not required to participate in the study. This retrospective study was conducted at a single facility (an acute-phase community hospital with 300 beds). We extracted the medical records of patients aged ≥ 65 years who were hospitalized at our institution between April 2014 and March 2016 and who were diagnosed with aspiration pneumonia as their primary disease. We selected patients who met the criteria of CAP according to the clinical guidelines of the American Thoracic Society and Infectious Disease Society of America. Patients with hospital-acquired pneumonia (HAP) (Figure 1) were excluded.3 The diagnosis of aspiration pneumonia was defined based on clinical symptoms indicative of pneumonia (i.e., cough, sputum, and fever), infiltration on chest imaging (chest X-ray or computed tomography), and findings of aspiration assessed by a trained speech therapist (ST) and/or nurse in rehabilitation programs.