Long-term morbidity and mortality after hospitalization with community-acquired pneumonia: a population-based cohort study

Abstract

Little is known about the long-term sequelae of community-acquired pneumonia (CAP). Therefore, we describe the long-term morbidity and mortality of patients after pneumonia requiring hospitalization. We specifically hypothesized that the Pneumonia Severity Index (PSI), designed to predict 30-day pneumonia-related mortality, would also be associated with longer-term all-cause mortality. Between 2000 and 2002, 3415 adults with CAP admitted to 6 hospitals in Edmonton, Alberta, Canada, were prospectively enrolled in a population-based cohort. At the time of hospital admission, demographic, clinical, and laboratory data were collected and the PSI was calculated for each patient. Postdischarge outcomes through to 2006 were ascertained using multiple linked administrative databases. Outcomes included all-cause mortality, hospital admissions, and re-hospitalization for pneumonia over a maximum of 5.4 years of follow-up. Follow-up data were available for 3284 (96%) patients; 66%were > or =65 years of age, 53% were male, and according to the PSI fully 63% were predicted to have greater than 18% 30-day pneumonia-related mortality (that is, PSI class IV-V). Median follow-up was 3.8 years. The 30-day, 1-year, and end of study mortality rates were 12%, 28%, and 53%, respectively. Overall, 82(19%) patients aged <45 years died compared with 1456 (67%) patients aged > or =65 years (hazard ratio [HR], 5.07; 95% confidence interval [CI], 4.06-6.34). Male patients were more likely to die than female patients during follow-up (971 [56%] vs. 767 [49%], respectively; HR, 1.20; 95% CI, 1.13-1.37). Initial PSI classification predicted not only 30-day mortality, but also long-term postdischarge mortality, with 92 (15%) of PSI class I-II patients dying compared with 616 (82%) PSI class V patients (HR, 11.80; 95% CI, 4.70-14.70). Of 2950 patients who survived the initial CAP hospitalization, 72% were hospitalized again (median, 2 admissions over follow-up) and 16% were re-hospitalized with pneumonia. In conclusion, long-term morbidity and mortality are high following hospitalization for pneumonia and are strongly correlated with initial PSI class. This suggests that patients with pneumonia, especially those with PSI class IV and V at admission, might need better attention paid to preventive strategies and much closer follow-up due to their elevated risk of subsequent adverse events and increased health resource utilization.