title: A claims-based Markov model for Crohn's disease.
abstract: BACKGROUND
  Crohn's disease is a chronic condition that often presents in early adulthood.
  
  
  OBJECTIVE
  To evaluate health care costs and costs per quality-adjusted life year (QALY) for Crohn's disease.
  
  
  METHODS
  A Markov model was developed using administrative claims data for patients aged > or = 18 years with > or = 3 years of continuous enrolment from 2000 to 2008 and > or =2 Crohn's disease claims. Disease states (remission, mild-moderate, moderate-severe, and severe-fulminant) were defined using the American College of Gastroenterology treatment guidelines criteria. Transition probabilities were calculated from consecutive 6-month periods. Costs were determined from paid claims and QALY utilities were obtained from the literature. The model assumed a 30-year-old patient at the time of entry into the model.
  
  
  RESULTS
  There were 40 063 patients identified, with a total of 420 773 cycles [remission (197 111; 46.8%), mild-moderate (44 024; 10.5%), moderate-severe (132 695; 31.5%), severe-fulminant (46 925; 11.2%)]. The costs/QALY for remission, mild-moderate, moderate-severe, and severe-fulminant disease states respectively were $2896, $8428, $11 518 and $69 277 for males and $2896, $8426, $22 633 and $69 412 for females.
  
  
  CONCLUSIONS
  Overall, health care costs for patients with Crohn's disease increased with disease severity. Although the probabilities of transitioning from other health states to the severe-fulminant disease state were low, the cost/QALY was high.
authors.affiliation: University of Arizona College of Pharmacy, Tucson, 85721-0202, USA. malone@pharmacy.arizona.edu
authors.forename: D C
authors.initials: DC
authors.lastname: Malone
authors.forename: H C
authors.initials: HC
authors.lastname: Waters
authors.forename: J
authors.initials: J
authors.lastname: Van Den Bos
authors.forename: J
authors.initials: J
authors.lastname: Popp
authors.forename: K
authors.initials: K
authors.lastname: Draaghtel
authors.forename: M I
authors.initials: MI
authors.lastname: Rahman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003424:Crohn Disease / Q000191:economics* / Q000628:therapy; D005260:Female; D017048:Health Care Costs; D006801:Humans; D008297:Male; D008390:Markov Chains; D008875:Middle Aged; D019057:Quality-Adjusted Life Years; D055815:Young Adult