title: Comorbidities and the risk of mortality in patients with bronchiectasis: an international multicentre cohort study.
abstract: Patients with bronchiectasis often have concurrent comorbidities, but the nature, prevalence, and impact of these comorbidities on disease severity and outcome are poorly understood. We aimed to investigate comorbidities in patients with bronchiectasis and establish their prognostic value on disease severity and mortality rate.
  
  
  
  An international multicentre cohort analysis of outpatients with bronchiectasis from four European centres followed up for 5 years was done for score derivation. Eligible patients were those with bronchiectasis confirmed by high-resolution CT and a compatible clinical history. Comorbidity diagnoses were based on standardised definitions and were obtained from full review of paper and electronic medical records, prescriptions, and investigator definitions. Weibull parametric survival analysis was used to model the prediction of the 5 year mortality rate to construct the Bronchiectasis Aetiology Comorbidity Index (BACI). We tested the BACI as a predictor of outcomes and explored whether the BACI added further prognostic information when used alongside the Bronchiectasis Severity Index (BSI). The BACI was validated in two independent international cohorts from the UK and Serbia.
  
  
  
  Between June 1, 2006, and Nov 22, 2013, 1340 patients with bronchiectasis were screened and 986 patients were analysed. Patients had a median of four comorbidities (IQR 2-6; range 0-20). 13 comorbidities independently predicting mortality rate were integrated into the BACI. The overall hazard ratio for death conferred by a one-point increase in the BACI was 1·18 (95% CI 1·14-1·23; p<0·0001). The BACI predicted 5 year mortality rate, hospital admissions, exacerbations, and health-related quality of life across all BSI risk strata (p<0·0001 for mortality and hospital admissions, p=0·03 for exacerbations, p=0·0008 for quality of life). When used in conjunction with the BSI, the combined model was superior to either model alone (p=0·01 for combined vs BACI; p=0·008 for combined vs BSI).
  
  
  
  Multimorbidity is frequent in bronchiectasis and can negatively affect survival. The BACI complements the BSI in the assessment and prediction of mortality and disease outcomes in patients with bronchiectasis.
  
  
  
  European Bronchiectasis Network (EMBARC).
authors.affiliation: Department of Respiratory Medicine, Galway University Hospitals, Galway, Ireland; Institute of Cell and Molecular Biosciences and Institute for Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK; Lung Biology Group, National University of Ireland, Galway, Ireland. Electronic address: melissajanefriel@gmail.com.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: McDonnell
authors.affiliation: Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Cardio-thoracic unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Aliberti
authors.affiliation: Department of Respiratory Medicine, University Hospital Gasthuisberg, Leuven, Belgium; Department of Respiratory Medicine, AZ Nikolaas, Sint-Niklaas, Belgium.
authors.forename: Pieter C
authors.initials: PC
authors.lastname: Goeminne
authors.affiliation: Division of Pulmonary Diseases and Critical Care, South Texas Veterans Health Care System and University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
authors.forename: Marcos I
authors.initials: MI
authors.lastname: Restrepo
authors.affiliation: Scottish Centre for Respiratory Research, University of Dundee, Dundee, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Finch
authors.affiliation: School of Medicine and Surgery, University of Milan Bicocca, Respiratory Unit, AO San Gerardo, Monza, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Pesci
authors.affiliation: Department of Respiratory Medicine, University Hospital Gasthuisberg, Leuven, Belgium.
authors.forename: Lieven J
authors.initials: LJ
authors.lastname: Dupont
authors.affiliation: Scottish Centre for Respiratory Research, University of Dundee, Dundee, UK.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Fardon
authors.affiliation: Host Defence Unit, Royal Brompton Hospital, London, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Wilson
authors.affiliation: Host Defence Unit, Royal Brompton Hospital, London, UK.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Loebinger
authors.affiliation: Institute for Pulmonary Diseases of Vojvodina Sremska Kamenica, Sremska Kamenica, Serbia; Faculty of Medicine, University of Novi Sad, Serbia.
authors.forename: Dusan
authors.initials: D
authors.lastname: Skrbic
authors.affiliation: Institute for Pulmonary Diseases of Vojvodina Sremska Kamenica, Sremska Kamenica, Serbia; Faculty of Medicine, University of Novi Sad, Serbia.
authors.forename: Dusanka
authors.initials: D
authors.lastname: Obradovic
authors.affiliation: Institute of Cell and Molecular Biosciences and Institute for Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Anthony
authors.initials: A
authors.lastname: De Soyza
authors.affiliation: Institute of Cell and Molecular Biosciences and Institute for Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Ward
authors.affiliation: Lung Biology Group, National University of Ireland, Galway, Ireland; Department of Anesthesia, Keenan Research Centre for Biomedical Science, St Michael's Hospital, University of Toronto, Toronto, ON, Canada.
authors.forename: John G
authors.initials: JG
authors.lastname: Laffey
authors.affiliation: Department of Respiratory Medicine, Galway University Hospitals, Galway, Ireland.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Rutherford
authors.affiliation: Scottish Centre for Respiratory Research, University of Dundee, Dundee, UK.
authors.forename: James D
authors.initials: JD
authors.lastname: Chalmers
mesh_terms: D000368:Aged; D001987:Bronchiectasis / Q000401:mortality*; D015331:Cohort Studies; D015897:Comorbidity; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D011788:Quality of Life; D012307:Risk Factors; D012720:Severity of Illness Index; D015996:Survival Rate