Silent aspiration predicts mortality in older adults with aspiration pneumonia admitted to acute hospitals

Abstract

Aim: Aspiration pneumonia is a common disease resulting in poor outcomes for older adults. It is known that silent aspiration might lead to aspiration pneumonia, but its role in this is unclear. The aim of the present study was to investigate whether silent aspiration is associated with mortality in aspiration pneumonia patients.

Methods: A multicenter (acute hospital) study including 170 aspiration pneumonia patients was carried out. Cough latency time after inhalation of 1% citric acid mist was used to assess silent aspiration. Patients were divided into two groups: silent aspirator (SA) and no-SA groups based on the latency time of ≥29/<29 s.

Results: The mean age of the participants was 84.0 ± 8.8 years. A total of 82% of them had moderate aspiration pneumonia. A total of 99 (58.2%) patients were in the SA group. Silent aspiration patients were more likely to be inactive compared with those in the no-SA group (Barthel Index score 5 [IQR 0-45] vs 30 [IQR 5-65], P = 0.023) and had worse oral conditions (Oral Health Assessment Tool score 5.3 ± 3.2 vs 3.8 ± 3.1, P = 0.003). Nine of the SA patients and one of the no-SA patients (P = 0.047) died within a month. Multivariate regression analysis showed that silent aspiration was associated with mortality after adjusting for confounders (odds ratio 2.65, 95% CI 1.01-6.98, P = 0.049).

Conclusions: Silent aspiration detected by a cough latency test can predict 1-month mortality in older patients with aspiration pneumonia. More studies are required to investigate whether enhancing cough reflex treatments would help patients recover from aspiration pneumonia. Geriatr Gerontol Int 2018; 18: 828-832.

Keywords: hospitalized patients; observational study; pneumonia; respiratory defense; silent aspiration.