Risk factors for mortality in aspiration pneumonia: a single-center retrospective observational study

Aspiration pneumonia (AP) is the leading cause of death among the elderly in Japan. The factors associated with the survival of elderly patients with AP are investigated in this retrospective observational study. Patients with AP over the age of 60 who were assessed for swallowing function in our hospital between April 2015 and March 2016 were eligible. Data on patients' body mass index (BMI), food consistency, and Karnofsky performance status were collected from medical records in hospital and again after recovery. Following hospital discharge, eligible patients were sent questionnaires containing information about their physical conditions, such as body weight and the Japanese version of the functional independence measure. Respondents were divided into two groups: those who died and those who survived, and the factors associated with patient mortality were investigated. There were 19 responses from 50 eligible patients, and seven patients died. The participants' average age was 81 years (SD 9.32). There were ten male participants (52.6%, p=1.00), and there were no significant differences in the mortality and survival groups. The most significant finding was that BMI was significantly lower in the patients who died (p=0.037, Cohen's d=1.10). Fisher's exact tests clearly demonstrated that patients with a BMI <19.9 had a higher mortality rate (p=0.017). Lower BMI may be associated with increased mortality in elderly patients with a history of AP. In general practice, BMI is simple to measure and may allow for an easy assessment of the risk of AP-related mortality.