title: 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.
authors.affiliation: Department of Medicine, Faculty of Medicine and Dentistry.
authors.forename: T T
authors.initials: TT
authors.lastname: Dang
authors.affiliation: School of Public Health, University of Alberta, Edmonton.
authors.forename: D T
authors.initials: DT
authors.lastname: Eurich
authors.affiliation: School of Public Health, University of Alberta, Edmonton.
authors.forename: D L
authors.initials: DL
authors.lastname: Weir
authors.affiliation: Department of Medicine, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: T J
authors.initials: TJ
authors.lastname: Marrie
authors.affiliation: Department of Medicine, Faculty of Medicine and Dentistry School of Public Health, University of Alberta, Edmonton.
authors.forename: S R
authors.initials: SR
authors.lastname: Majumdar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011014:Pneumonia / Q000453:epidemiology* / Q000473:pathology; D011446:Prospective Studies; D012008:Recurrence; D012307:Risk Factors; D012720:Severity of Illness Index
keywords: community-acquired pneumonia; population-based cohort; recurrent pneumonia; risk factors
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