Hospital mortality of patients admitted with community-acquired pneumonia (CAP) has been well described. However, the long-term survival of those discharged alive is less clear. We sought to determine long-term survival of patients hospitalized with CAP and compare the outcome with controls hospitalized for reasons other than CAP.
We performed a matched case-control analysis using the Medicare hospital discharge database from the first quarter of 1997. We compared all Medicare recipients 65 years or older hospitalized with CAP and controls matched for age, sex, and race hospitalized for reasons other than CAP. We measured 1-year mortality determined from the Medicare Beneficiary Entitlement file and the Social Security Administration.
We identified 158 960 CAP patients and 794 333 hospitalized controls. Hospital mortality rates for the CAP cohort and hospitalized controls were 11.0% and 5.5%, respectively (P<.001). One-year mortality rates for the CAP cohort and hospitalized controls were 40.9% and 29.1%, respectively (P<.001). One-year mortality rates in hospital survivors of the CAP and control cohorts were 33.6% and 24.9%, respectively (P<.001). The difference in mortality between the CAP and control cohorts was not explained by underlying disease. Standardized against the general population, the risk of death for both cohorts decreased monthly but was still elevated 1 year after hospital discharge. The standardized mortality ratio was 2.69 (95% confidence interval, 2.47-2.93) for CAP patients and 1.93 (95% confidence interval, 1.79-2.08) for hospital controls.
Almost half of all elderly patients admitted for CAP die in the subsequent year, with most deaths occurring after hospital discharge. The mortality is considerably higher than that of either the general population or a control population hospitalized for reasons other than CAP.