Muscle Mass Loss Is a Potential Predictor of 90-Day Mortality in Older Adults with Aspiration Pneumonia

Objectives: To investigate the association between loss of muscle mass and aspiration pneumonia (AP).

Design: Prospective observational cohort.

Setting: Acute geriatric hospital.

Participants: Individuals admitted to the hospital for AP (N = 151; mean age 85.9; 49.7% male).

Measurements: Appendicular skeletal muscle index (ASMI; appendicular skeletal muscle mass divided by height squared) was used to evaluate muscle mass. Data on age, sex, body mass index, Mini Nutritional Assessment-Short Form score, Barthel Index score, Charlson Comorbidity Index score, and pneumonia severity (Japanese version of the CURB-65 (C (confusion), U (blood urea nitrogen ≥20 mg/dL), R (respiratory rate ≥30 breaths/min), B (systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg), 65 (aged ≥65) severity score (A-DROP)) were obtained. Outcomes included 30- and 90-day mortality.

Results: Mild, moderate, severe, and extremely severe AP were observed in 1.3%, 70.2%, 25.8%, and 2.6% of participants, respectively. On Kaplan-Meier analysis, participants in the lowest ASMI quartile for each sex were more likely to die than those in the other quartiles (log-lank test P = .005). Multivariate logistic analyses showed that ASMI and A-DROP were independent predictors of 90-day mortality; only A-DROP was a significant predictor of 30-day mortality (P < .001). Cox regression analysis also showed that the first ASMI quartile was independently associated with mortality (hazard ratio = 2.19; 95% confidence interval = 1.06-4.52; P = .03).

Conclusion: Low muscle mass is a potential predictor of long-term mortality in individuals with AP. Prospectively preventing muscle mass deterioration may be beneficial for recovery from AP in older adults.