Risk factors and interventions for developing recurrent pneumonia in older adults.

Background: Pneumonia is common among older adults and often recurrent. Several studies have been conducted on the risk factors for pneumonia; however, little is known about the risk factors for recurrent pneumonia. This study aimed to identify the risk factors for developing recurrent pneumonia among older adults and to investigate methods of prevention.

Methods: We analysed the data of 256 patients aged 75 years or older who were admitted for pneumonia between June 2014 and May 2017. Moreover, we reviewed the medical records for the subsequent 3 years and defined the readmission caused by pneumonia as recurrent pneumonia. Risk factors for recurrent pneumonia were analysed using multivariable logistic regression analysis. Differences in the recurrence rate based on the types and use of hypnotics were also evaluated.

Results: Of the 256 patients, 90 (35.2%) experienced recurrent pneumonia. A low body mass index (OR: 0.91; 95% CI: 0.83‒0.99), history of pneumonia (OR: 2.71; 95% CI: 1.23‒6.13), lung disease as a comorbidity (OR: 4.73; 95% CI: 2.13‒11.60), taking hypnotics (OR: 2.16; 95% CI: 1.18‒4.01) and taking histamine-1 receptor antagonist (H1RA) (OR: 2.38; 95% CI: 1.07‒5.39) were risk factors. Patients taking benzodiazepine as hypnotics were more likely to experience recurrent pneumonia than patients not taking hypnotics (OR: 2.29; 95% CI: 1.25-4.18).

Conclusion: We identified several risk factors for recurrent pneumonia. Among them, restricting the use of H1RA and hypnotics, in particular benzodiazepines, may be useful in preventing the recurrence of pneumonia in adults aged 75 years or older.