Risk factors for postextubation pneumonia using diagnosis procedure combination and claims data in Japan.

Intubation-related pneumonia negatively affects patient outcomes. Aspiration pneumonia occurring after extubation due to swallowing dysfunction, conceptualized as postextubation pneumonia (PEP), remains underrecognized as a distinct clinical entity. This single-center, retrospective study aimed to evaluate the incidence and risk factors for PEP using large-scale　diagnosis procedure combination (DPC) and administrative claims data. We reviewed all patients who underwent elective surgery under general anesthesia between April 2016 and March 2023. Patients undergoing emergency surgery or lacking data on activities of daily living (ADL) or body mass index (BMI) were excluded. Patients who developed pneumonia after extubation and required newly initiated antibiotic therapy were classified as PEP cases. Ventilator-associated pneumonia (VAP) cases were identified according to standard definitions. Among 31 828 eligible patients, 212 (0.67%) developed PEP, which occurred more frequently than VAP. Risk factors for PEP included advanced age, male sex, low BMI, impaired consciousness, and reduced ADL. Surgical sites associated with PEP included the gastrointestinal tract, respiratory system, thoracic cavity, cardiovascular and nervous systems, and head, neck, and face. Smoking status was not significantly associated with PEP. These findings highlight PEP as a clinically important and potentially preventable complication. Targeted dysphagia screening and perioperative multidisciplinary interventions may help reduce its incidence.