title: Effect of pulmonary exacerbations treated with oral antibiotics on clinical outcomes in cystic fibrosis.
abstract: Despite extensive knowledge regarding the effect of pulmonary exacerbations treated with intravenous antibiotics on clinical outcomes in cystic fibrosis (CF), there is little known about the role of milder pulmonary exacerbations treated with oral antibiotics (oPEx).
  
  
  
  This was a retrospective cohort study of patients with CF followed at the Hospital for Sick Children and St. Michael's Hospital from 2009 to 2014. We evaluated the effect of oPEx on short-term clinical outcomes as the proportion of oPEx events in which 100% or 90% of baseline FEV1% predicted was recovered at the end of treatment. We then examined the association of the number of oPEx events in the past 12 months on lung function (FEV1% predicted) and nutritional status (body mass index (BMI) z-score) using a mixed-effects model.
  
  
  
  There were a total of 2608 oPEx events in 570 subjects during the study period. In over half (53.4%) of oPEx events, lung function was already at 90% or higher of baseline FEV1at the initiation of oral antibiotic therapy and 82% were at 90% or higher of baseline FEV1at follow-up. In individuals with CF, one or more oPex events in the previous 12 months were associated with decreased FEV1compared with 12 months periods without oPex events. When the cumulative effect of oPExs on lung function was examined over the entire study period, patients with six or more oPEx events had the steepest rate of FEV1decline. oPEx events were not associated with changes in BMI.
  
  
  
  oPEx events are associated with short-term loss of FEV1and have a negative effect on lung function over time.
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sanja
authors.identifier: 0000-0001-7931-8051
authors.initials: S
authors.lastname: Stanojevic
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Alexandra
authors.initials: A
authors.lastname: McDonald
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Valerie
authors.initials: V
authors.lastname: Waters
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: MacDonald
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Horton
authors.affiliation: Division of Respirology, Keenan Research Centre of Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada.|Department of Medicine, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Tullis
authors.affiliation: Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Felix
authors.identifier: 0000-0003-4057-6592
authors.initials: F
authors.lastname: Ratjen
mesh_terms: D061605:Administration, Intravenous; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002648:Child; D003550:Cystic Fibrosis / Q000382:microbiology* / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D009752:Nutritional Status; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents
keywords: Cystic Fibrosis; Respiratory Infection; Respiratory Measurement