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Predictors of pulmonary exacerbations in patients with cystic fibrosis infected with multi-resistant bacteria
  1. J K Block1,
  2. K L Vandemheen1,
  3. E Tullis3,
  4. D Fergusson1,
  5. S Doucette1,
  6. D Haase4,
  7. Y Berthiaume5,
  8. N Brown6,
  9. P Wilcox7,
  10. P Bye2,
  11. S Bell8,
  12. M Noseworthy9,
  13. L Pedder10,
  14. A Freitag10,
  15. N Paterson11,
  16. S D Aaron1
  1. 1Ottawa Health Research Institute, University of Ottawa, Ottawa, ON, Canada
  2. 2Woolcock Institute, Sydney, NSW, Australia
  3. 3St Michael’s Hospital, Toronto, ON, Canada
  4. 4Dalhousie University, Halifax, NS, Canada
  5. 5Universite de Montreal, Montreal, QC, Canada
  6. 6University of Alberta, Edmonton, AB, Canada
  7. 7University of British Columbia, Vancouver, BC, Canada
  8. 8The Prince Charles Hospital, Brisbane, Qld, Australia
  9. 9Memorial University, St John’s, NF, Canada
  10. 10McMaster University, Hamilton, ON, Canada
  11. 11University of Western Ontario, London, ON, Canada
  1. Correspondence to:
    Dr S D Aaron
    Ottawa Hospital, General Campus, 501 Smyth Road, Mailbox 211, Ottawa, Ontario, Canada K1H 8L6; saaron{at}


Background: This study examined characteristics of adult and adolescent patients with cystic fibrosis (CF) to determine factors associated with an increased risk of pulmonary exacerbations.

Methods: 249 patients with CF infected with multidrug resistant bacteria were recruited and prospectively followed for up to 4.5 years until they experienced a pulmonary exacerbation severe enough to require intravenous antibiotics. Multivariable regression analyses were used to compare the characteristics of patients who experienced an exacerbation with those who did not.

Results: 124 of the 249 patients (50%) developed a pulmonary exacerbation during the first year and 154 (62%) experienced an exacerbation during the 4.5 year study period. Factors predictive of exacerbations in a multivariable survival model were younger age (OR 0.98, 95% CI 0.96 to 0.99), female sex (OR 1.45, 95% CI 1.07 to 1.95), lower forced expiratory volume in 1 second (FEV1) (OR 0.98, 95% CI 0.97 to 0.99), and a previous history of multiple pulmonary exacerbations (OR 3.16, 95% CI 1.93 to 5.17). Chronic use of inhaled corticosteroids was associated with an increased risk of exacerbation (OR 1.92, 95% CI 1.00 to 3.71) during the first study year.

Conclusions: Patients who experience pulmonary exacerbations are more likely to be younger, female, using inhaled steroids, have a lower FEV1, and a history of multiple previous exacerbations. It is hoped that knowledge of these risk factors will allow better identification and closer monitoring of patients who are at high risk of exacerbations.

  • BMI, body mass index
  • CF, cystic fibrosis
  • FEV1, forced expiratory volume in 1 second
  • FVC, forced vital capacity
  • cystic fibrosis
  • pulmonary exacerbations
  • bacterial resistance
  • lung infections
  • risk factors

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  • Published Online First 14 July 2006

  • Supported by grants from The Canadian Institutes of Health Research, The Australian Cystic Fibrosis Research Trust, Astra-Zeneca Canada Inc (unrestricted research grant), and The Canadian Cystic Fibrosis Foundation.

  • Competing interests: none declared.

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