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Exacerbation frequency and clinical outcomes in adult patients with cystic fibrosis
  1. Kaïssa de Boer1,
  2. Katherine L Vandemheen1,
  3. Elizabeth Tullis2,
  4. Steve Doucette1,
  5. Dean Fergusson1,
  6. Andreas Freitag3,
  7. Nigel Paterson4,
  8. Mary Jackson5,
  9. M Diane Lougheed6,
  10. Vijay Kumar7,
  11. Shawn D Aaron1
  1. 1The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
  2. 2University of Toronto, Toronto, Ontario, Canada
  3. 3McMaster University, Hamilton, Ontario, Canada
  4. 4University of Western Ontario, London, Ontario, Canada
  5. 5Grand River Hospital, Kitchener, Ontario, Canada
  6. 6Queen's University, Kingston, Ontario, Canada
  7. 7Sudbury Regional Hospital, Sudbury, Ontario, Canada
  1. Correspondence to Shawn D Aaron, The Ottawa Hospital, General Campus, University of Ottawa, 501 Smyth Road, Ottawa, Ontario, Canada K1H 8L6; saaron{at}


Background Despite advances in treatment of cystic fibrosis (CF), pulmonary exacerbations remain common. The aim of this study was to determine if frequent pulmonary exacerbations are associated with greater declines in lung function, or an accelerated time to death or lung transplantation in adults with CF.

Methods A 3-year prospective cohort study was conducted on 446 adult patients with CF from Ontario, Canada who could spontaneously produce sputum. Patients enrolled from 2005 to 2008 and were stratified into groups based upon their exacerbation rates over the 3 year study: <1 exacerbation/year (n=140), 1–2 exacerbations/year (n=160) and >2 exacerbations/year (n=146). Exacerbations were defined as acute/subacute worsening of respiratory symptoms severe enough to warrant oral or intravenous antibiotics. Patient-related factors associated with frequent exacerbations were determined, and clinical outcomes were compared among the three exacerbation groups.

Results Patients with frequent exacerbations were more likely to be female, diabetic and have poorer baseline lung function. Patients with >2 exacerbations/year had an increased risk of experiencing a 5% decline from baseline forced expiratory volume in 1 s (FEV1); unadjusted HR 1.47 (95% CI 1.07 to 2.01, p=0.02), adjusted HR 1.55 (95% CI 1.10 to 2.18, p=0.01) compared with patients with <1 exacerbation/year. Patients with >2 exacerbations/year also had an increased risk of lung transplant or death over the 3 year study; unadjusted HR 12.74 (95% CI 3.92 to 41.36, p<0.0001), adjusted HR 4.05 (95% CI 1.15 to 14.28, p=0.03).

Conclusions Patients with CF with frequent exacerbations appear to experience an accelerated decline in lung function, and they have an increased 3 year risk of death or lung transplant.

  • Pulmonary infection
  • pulmonary function tests
  • antibiotics
  • lung transplant
  • bacterial infection
  • clinical epidemiology
  • cystic fibrosis

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  • Funding The Canadian Institutes of Health Research, Canadian Cystic Fibrosis Foundation and Ontario Thoracic Society. The funding sources had no role in the design and conduct of the study, analysis or interpretation of the data, preparation or final approval of the manuscript, or the decision to submit the manuscript for publication.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the The Ottawa Hospital, and the other six hospitals that were involved in this study.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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