title: The bronchiectasis severity index. An international derivation and validation study.
abstract: BACKGROUND
  There are no risk stratification tools for morbidity and mortality in bronchiectasis. Identifying patients at risk of exacerbations, hospital admissions, and mortality is vital for future research.
  
  
  OBJECTIVE
  This study describes the derivation and validation of the Bronchiectasis Severity Index (BSI).
  
  
  METHODS
  Derivation of the BSI used data from a prospective cohort study (Edinburgh, UK, 2008-2012) enrolling 608 patients. Cox proportional hazard regression was used to identify independent predictors of mortality and hospitalization over 4-year follow-up. The score was validated in independent cohorts from Dundee, UK (n = 218); Leuven, Belgium (n = 253); Monza, Italy (n = 105); and Newcastle, UK (n = 126).
  
  
  RESULTS
  Independent predictors of future hospitalization were prior hospital admissions, Medical Research Council dyspnea score greater than or equal to 4, FEV1 < 30% predicted, Pseudomonas aeruginosa colonization, colonization with other pathogenic organisms, and three or more lobes involved on high-resolution computed tomography. Independent predictors of mortality were older age, low FEV1, lower body mass index, prior hospitalization, and three or more exacerbations in the year before the study. The derived BSI predicted mortality and hospitalization: area under the receiver operator characteristic curve (AUC) 0.80 (95% confidence interval, 0.74-0.86) for mortality and AUC 0.88 (95% confidence interval, 0.84-0.91) for hospitalization, respectively. There was a clear difference in exacerbation frequency and quality of life using the St. George's Respiratory Questionnaire between patients classified as low, intermediate, and high risk by the score (P < 0.0001 for all comparisons). In the validation cohorts, the AUC for mortality ranged from 0.81 to 0.84 and for hospitalization from 0.80 to 0.88.
  
  
  CONCLUSIONS
  The BSI is a useful clinical predictive tool that identifies patients at risk of future mortality, hospitalization, and exacerbations across healthcare systems.
authors: 1 Tayside Respiratory Research Group, University of Dundee, Dundee, United Kingdom.
authors: James D
authors: JD
authors: Chalmers
authors: Pieter
authors: P
authors: Goeminne
authors: Stefano
authors: S
authors: Aliberti
authors: Melissa J
authors: MJ
authors: McDonnell
authors: Sara
authors: S
authors: Lonni
authors: John
authors: J
authors: Davidson
authors: Lucy
authors: L
authors: Poppelwell
authors: Waleed
authors: W
authors: Salih
authors: Alberto
authors: A
authors: Pesci
authors: Lieven J
authors: LJ
authors: Dupont
authors: Thomas C
authors: TC
authors: Fardon
authors: Anthony
authors: A
authors: De Soyza
authors: Adam T
authors: AT
authors: Hill
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001987:Bronchiectasis / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D003661:Decision Support Techniques; D018450:Disease Progression; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012129:Respiratory Function Tests; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires