Characteristic Factors of Aspiration Pneumonia to Distinguish from Community-Acquired Pneumonia among Oldest-Old Patients in Primary-Care Settings of Japan

Background: Aspiration pneumonia (AsP), a phenotype of community-acquired pneumonia (CAP), is a common and problematic disease with symptomless recurrence and fatality in old adults. Characteristic factors for distinguishing AsP from CAP need to be determined to manage AsP. No such factorial markers in oldest-old adults, who are often seen in the primary-care settings, have yet been established. Methods: From the database of our Primary Care and General Practice Study, including the general backgrounds, clinical conditions and laboratory findings collected by primary care physicians and general practitioners, the records of 130 patients diagnosed with either AsP (n = 72) or CAP (n = 58) were extracted. Characteristic factors associated with the diagnosis of AsP were statistically compared between AsP and CAP. Results: The patients were older in the AsP group (median 90 years old) than in the CAP group (86 years old). The body temperature, heart rate, and diastolic blood pressure were lower in the patients with AsP than in those with CAP. Witnessed meal dysphagia by families and caregivers was reported only in AsP. Living in a nursing home, comorbidities of cerebral infarction and dementia (as positive factors) and hypertension (as a negative factor) were considered predictive to diagnose AsP in a stepwise logistic regression analysis. Conclusions: Among oldest-old adults in primary-care settings, living in a nursing home and the dysphagia risks are suggested to be characteristic factors for diagnosing AsP. Age and some relevant clinical information may help manage AsP and also be useful for families and caregivers.