Rates and risk factors for recurrent pneumonia in patients hospitalized with community-acquired pneumonia: population-based prospective cohort study with 5 years of follow-up

Abstract

Background: The rates and risk factors for developing recurrent pneumonia following hospitalization with community-acquired pneumonia (CAP) are poorly understood.

Methods: We examined a population-based cohort of patients with CAP who survived hospital admission and who were free of pneumonia for at least 3 months. We collected clinical, functional, and medication-related information and pneumonia severity index (PSI). Using linked databases we followed patients for 5 years and captured any clinical episode of pneumonia 90 days or more post-discharge. We used Cox proportional hazards models (adjusted for age, sex, PSI, functional status, medications) to determine rates and independent correlates of recurrent pneumonia.

Results: The final cohort included 2709 inpatients; 43% were 75 years or older, 34% were not fully independent, and 56% had severe pneumonia. Over 5 years of follow-up, 245 (9%; 95% confidence interval [CI], 8%-10%) patients developed recurrent pneumonia, and 156 (64%) of these episodes required hospitalization. Rate of recurrence was 3.0/100 person-years and median time to recurrence was 317 days (interquartile range, 177-569); 32 (13%) patients had 2 or more recurrences. In multivariable analyses only age >75 years (adjusted P = .047) and less than fully independent functional status (12% recurrence rate with impaired functional status vs 7% for fully independent; adjusted hazard ratio, 1.7; 95% CI, 1.3-2.2; P < .001) were significantly associated with recurrent pneumonia.

Conclusions: One of 11 patients who survived CAP hospitalization had recurrent pneumonia over 5 years and those with impaired functional status were at particularly high risk. Recurrent pneumonia is common and more attention to preventive strategies at discharge and closer follow-up over the long-term seem warranted.

Keywords: community-acquired pneumonia; population-based cohort; recurrent pneumonia; risk factors.

Figure 1.

Rates of recurrent pneumonia according to functional status: cumulative incidence curves.