title: Acute cellular rejection is a risk factor for bronchiolitis obliterans syndrome independent of post-transplant baseline FEV1.
abstract: BACKGROUND
  Post-transplant baseline forced expiratory volume in 1 second (FEV(1)) constitutes a systematic bias in analyses of bronchiolitis obliterans syndrome (BOS). This retrospective study evaluates risk factors for BOS adjusting for the confounding of post-transplant baseline FEV(1).
  
  
  METHODS
  A multivariate survival and competing risk analysis of a large consecutive series of patients (n = 389) from a national center 1992 to 2004. Exclusion criteria were patients not surviving at least 3 months after transplantation (n = 39) and no available lung function measurements (n = 4).
  
  
  RESULTS
  The first maximum FEV(1) occurred at a median 183 days post-transplant. Freedom from BOS was 81%, 53%, 38% and 15%, and cumulative incidence of BOS was 18%, 43%, 57% and 77% at 1, 3, 5 and 10 years post-transplantation, respectively. Acute cellular rejection was independently associated with an increased cause-specific hazard of BOS (hazard ratio 1.4, confidence interval 1.1 to 1.8, p = 0.009). The absolute value of baseline FEV(1) was a significant confounder in all survival and competing risk analyses of BOS (p < 0.05).
  
  
  CONCLUSIONS
  Despite early diagnosis and prompt treatment, acute cellular rejection remains an independent risk factor for the development of BOS after adjusting for the confounding of post-transplant baseline FEV(1).
authors.affiliation: Department of Cardiology, Division of Lung Transplantation, Copenhagen University Hospital, Copenhagen, Denmark. cmburton@doctors.net.uk
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Burton
authors.forename: Martin
authors.initials: M
authors.lastname: Iversen
authors.forename: Jørn
authors.initials: J
authors.lastname: Carlsen
authors.forename: Jann
authors.initials: J
authors.lastname: Mortensen
authors.forename: Claus B
authors.initials: CB
authors.lastname: Andersen
authors.forename: Daniel
authors.initials: D
authors.lastname: Steinbrüchel
authors.forename: Thomas
authors.initials: T
authors.lastname: Scheike
mesh_terms: D000328:Adult; D001989:Bronchiolitis Obliterans / Q000453:epidemiology* / Q000401:mortality; D003643:Death; D005260:Female; D005541:Forced Expiratory Volume; D006084:Graft Rejection / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D016041:Heart-Lung Transplantation / Q000009:adverse effects / Q000473:pathology; D006801:Humans; D015994:Incidence; D008171:Lung Diseases / Q000145:classification / Q000601:surgery; D016040:Lung Transplantation / Q000009:adverse effects* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D017741:Survivors; D013997:Time Factors