title: Validation of a novel risk score for severity of illness in acute exacerbations of COPD.
abstract: BACKGROUND
  Clinicians lack a validated tool for risk stratification in acute exacerbations of COPD (AECOPD). We sought to validate the BAP-65 (elevated BUN, altered mental status, pulse > 109 beats/min, age > 65 years) score for this purpose.
  
  
  METHODS
  We analyzed 34,699 admissions to 177 US hospitals (2007) with either a principal diagnosis of AECOPD or acute respiratory failure with a secondary diagnosis of AECOPD. Hospital mortality and need for mechanical ventilation (MV) served as co-primary end points. Length of stay (LOS) and costs represented secondary end points. We assessed the accuracy of BAP-65 via the area under the receiver operating characteristic curve (AUROC).
  
  
  RESULTS
  Nearly 4% of subjects died while hospitalized and approximately 9% required MV. Mortality increased with increasing BAP-65 class, ranging from < 1% in subjects in class I (score of 0) to > 25% in those meeting all BAP-65 criteria (Cochran-Armitage trend test z = -38.48, P < .001). The need for MV also increased with escalating score (2% in the lowest risk cohort vs 55% in the highest risk group, Cochran-Armitage trend test z = -58.89, P < .001). The AUROC for BAP-65 for hospital mortality and/or need for MV measured 0.79 (95% CI, 0.78-0.80). The median LOS was 4 days, and mean hospital costs equaled $5,357. These also varied linearly with increasing BAP-65 score.
  
  
  CONCLUSIONS
  The BAP-65 system captures severity of illness and represents a simple tool to categorize patients with AECOPD as to their risk for adverse outcomes. BAP-65 also correlates with measures of resource use. BAP-65 may represent a useful adjunct in the initial assessment of AECOPDs.
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Washington Hospital Center, Washington, DC. Electronic address: andrew.shorr@gmail.com.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Shorr
authors.affiliation: Department of Clinical Research, MedMined Services, CareFusion, Marlborough, MA.
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Clinical Research, MedMined Services, CareFusion, Marlborough, MA; Brigham and Women's Hospital and Harvard Medical School, Boston, MA.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Johannes
authors.affiliation: Department of Clinical Research, MedMined Services, CareFusion, Marlborough, MA.
authors.forename: Ayla
authors.initials: A
authors.lastname: Yaitanes
authors.affiliation: Department of Clinical Research, MedMined Services, CareFusion, Marlborough, MA.
authors.forename: Ying P
authors.initials: YP
authors.lastname: Tabak
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019540:Area Under Curve; D001806:Blood Urea Nitrogen; D016009:Chi-Square Distribution; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011674:Pulse; D012372:ROC Curve; D012121:Respiration, Artificial; D018570:Risk Assessment / Q000379:methods*; D012720:Severity of Illness Index