Specific pathogens as predictors of poor long-term prognosis after hospital discharge for community-acquired pneumonia

Background: Some studies have reported that long-term prognosis after pneumonia is poor. Our aim was to determine predictors of long-term outcomes with special attention to community-acquired pneumonia (CAP) etiology. Methods: We studied 1930 patients who were hospitalized with CAP from January 2002 through November 2017 at Saitama Cardiovascular and Respiratory Center and were discharged alive. We conducted a retrospective study for calculation of survival rate using the Kaplan-Meier method and analysis of prognostic factors by multivariate analysis using a Cox proportional hazard model. Results: The median follow-up period was 442.5 (range 1-5514) days. During this period, 321 patients died. Median survival time was 11.9 years, and 1-year and 5-year survival rates were 93.8% and 74.0%, respectively. Among the patients' demographics factors, old age, poor performance status (PS) score, pneumococcal vaccination history, some underlying respiratory diseases, and chronic heart failure were significant independent factors of poor prognosis. Among pathogens, Streptococcus pneumoniae (hazard ratio [HR]: 1.35, 95% confidence interval [CI]: 1.03, 3.07, P = 0.038) and Pseudomonas aeruginosa (HR: 1.68, 95% CI: 1.07, 2.64, P = 0.024) were significant independent factors of poor prognosis, whereas influenza virus tended to predict a good prognosis (HR: 0.60, 95% CI: 0.36, 1.02, P = 0.058). Respiratory disease accounted for 59% of all causes of death after CAP, and the rate of death from pneumonia was the largest at 22%. Conclusion: Not only age, general condition, and comorbidities but also specific pathogens were predictors of long-term prognosis after hospital discharge for CAP.