Incidence and Mortality of Adults Hospitalized With Community-Acquired Pneumonia According to Clinical Course.

Background: After hospitalization for community-acquired pneumonia (CAP), patients' clinical course may progress to clinical improvement, clinical failure, or nonresolving pneumonia. The epidemiology and outcomes of patients with CAP according to clinical course has not been well studied. The objective of this study was to characterize the incidence and outcomes for each clinical course of hospitalized patients with CAP.

Methods: This was a secondary data analysis of the University of Louisville Pneumonia Study. Clinical course was classified as improvement, failure, and nonresolving. Objective criteria were used to define improvement and failure during the first week of hospitalization. If neither group of criteria were met, the course was classified as nonresolving. Incidence for each clinical course was calculated. Mortality was evaluated at different time points through the first year. P < .05 was considered statistically significant.

Results: A total of 7,449 patients were hospitalized with CAP during the study period. Improvement was documented in 5,732 patients (77%), failure was documented in 1,458 patients (20%), and nonresolving CAP was documented in 259 patients (3%). Mortality at 30 days was 6% for those who improved, 34% for those who failed, and 34% for those with nonresolving pneumonia. Mortality at 1 year was 23%, 52%, and 51%, respectively.

Conclusions: This study shows that > 75% of hospitalized patients with CAP will reach clinical improvement. One of two patients with clinical failure or nonresolving CAP may die 1 year after hospitalization. Understanding the pathogenesis of long-term mortality is critical to developing interventions.