title: A novel risk score to stratify severity of Crohn's disease hospitalizations.
abstract: OBJECTIVE
  Crohn's disease (CD) is a lifelong relapsing-remitting disease often requiring health-care contact, hospitalization, or surgery. General comorbidity indices were developed to predict mortality, which is rare in this population. There are limited tools to stratify these hospitalizations by severity.
  
  
  METHODS
  We used data obtained from the Nationwide Inpatient Sample 2004 to identify all CD-related hospitalizations using discharge diagnosis codes (International Classification of Diseases, 9th edition, Clinical Modification, ICD-9-CM, 555.x). Independent predictors on multivariate regression were identified and used to construct a quantitative risk score to predict severe hospitalizations (defined as requiring nonelective bowel surgery or hospitalization longer than 7 days). The performance of our risk score was compared with the Elixhauser and Charlson comorbidity indices, and validated in an independent sample of CD hospitalizations from 2007.
  
  
  RESULTS
  Our final study cohort consisted of 25,938 discharges, among which 6,169 were determined to be severe hospitalizations (23.8%). Independent predictors of disease severity included disease phenotype, anemia, malnutrition, and requirement for blood transfusion or total parenteral nutrition, as well as Clostridium difficile infection, admission to a teaching hospital, or inter-hospital transfer. The cumulative risk score ranged from 0 to 13 points, with scores >or=5 being considered to be of greater severity. A total of 15,330 (59.1%), 9,060 (34.9%), and 1,548 (6.0%) discharges were classified as being of low, intermediate, and high risk, respectively. An intermediate (odds ratio (OR) 2.63, 95% confidence interval (CI): 2.47-2.80) or high-risk score (OR 13.62, 95% CI: 12.12-15.33) was associated with a significantly higher adjusted risk of severe hospitalization.
  
  
  CONCLUSIONS
  Using administrative data, we propose a simple quantitative risk score to measure the severity of CD hospitalizations.
authors.affiliation: Division of Gastroenterology and Hepatology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA. aanantha@mcw.edu
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Ananthakrishnan
authors.forename: Emily L
authors.initials: EL
authors.lastname: McGinley
authors.forename: David G
authors.initials: DG
authors.lastname: Binion
authors.forename: Kia
authors.initials: K
authors.lastname: Saeian
mesh_terms: D019540:Area Under Curve; D016009:Chi-Square Distribution; D015897:Comorbidity; D003424:Crohn Disease / Q000453:epidemiology / Q000503:physiopathology*; D016208:Databases, Factual; D005260:Female; D017722:Hospital Charges; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D038801:International Classification of Diseases; D008297:Male; D012044:Regression Analysis; D020379:Risk Adjustment; D018570:Risk Assessment; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology