Prognostic factors associated with community-acquired aspiration pneumonia

BACKGROUND: Aspiration pneumonia (AP) represents about 5-24% of community-acquired pneumonias. This condition mainly affects elderly patients and causes a high mortality. Our objective was to quantify the AP mortality rate and to identify prognostic factors upon patients admission. PATIENTS AND METHOD: We underwent a retrospective observational study of a cohort of AP patients admitted to a tertiary care hospital during a 29 months period. The in-hospital mortality rate was calculated. To identify prognostic factors, basal characteristics of patients as well as their clinical presentation and complementary tests performed on admission were studied and intervals analyzed by univariate and multivariate techniques. Odds ratios and 95% confidence were estimated. RESULTS: Thirty six out of 105 admitted patients with AP died (cumulative mortality incidence rate 34%, 95% CI 25-44%). In the univariate analysis, demographic, clinical and complementary test variables were associated with mortality. Final logistic model revealed the following independent variables: living in a nursing home (OR = 3.4; 95% CI 1.1-10.9), high degree of dependence (OR = 0.3; 95% CI, 0.1-0.9), body temperature (OR = 0.5 per Celsius degree; CI, 0.3-1.0), serum creatinine levels (OR = 2.2 per mg/100 ml; 95% CI, 1.2-4.1) and LDH serum concentrations (OR = 1.5 per 100 IU/L; 95% CI, 1.1-2.0). CONCLUSIONS: The mortality of community-acquired AP is very high. In addition to clinical and biological parameters on admission such as body temperature and LDH and creatinine serum concentrations, living in a nursing home and having a high degree of dependence for the basic daily activities were identified as independent prognostic factors. An in-depth knowledge of prognostic factors related to pre-admission care and assistance is needed to decrease the mortality in these patients.