title: Results of a model analysis to estimate cost utility and value of information for intravenous immunoglobulin in Canadian adults with chronic immune thrombocytopenic purpura.
abstract: OBJECTIVE
  The aim of this work was to estimate the cost-effectiveness of intravenous immunoglobulin (IVIg) compared with oral prednisone as a treatment for Canadian adults with persistent chronic immune thrombocytopenic purpura (ITP).
  
  
  METHODS
  The lifetime costs and effectiveness of IVIg and prednisone were estimated from the perspective of a publicly funded health care system in Canada, using a Markov model that was developed based on a systematic clinical and economic review and recommendations of clinical experts in Canada. Transition probabilities (ie, point estimates and 95% CIs) were estimated from the studies identified in a systematic literature review using a random-effect meta-analysis; point estimates were weighted-mean values from the meta-analysis. No published studies directly estimate the utility weight for patients with relapsed or refractory ITP; therefore, a value of 0.76 was used, based on the mean of the utilities for thrombocytopenia without major bleeding or hemorrhagic stroke. Costs and incremental cost-effectiveness ratios were reported as year-2007 Can $.
  
  
  RESULTS
  The incremental costs and quality-adjusted life-years (QALYs) of IVIg versus prednisone were Can $8080 and 0.0071, respectively, resulting in an incremental cost-effectiveness ratio of Can $1.13 million/ QALY in the base-case analysis. The probability of IVIg being cost-effective was 0 if the maximum willingness-to-pay (WTP) value for an additional QALY was below Can $40,000. The probability that IVIg would be cost-effective was only 20%, even if the WTP increased to Can $100,000. The expected value of perfect information (EVPI) and expected value of partial perfect information (EVPPI) were 0 if the WTP was less than Can $30,000. If WTP increased to Can $100,000, the EVPI was Can $1700, and the EVPPI was Can $1010 for utility weights of relapse/refractory states, Can $136 for initial response rates of the treatments, and Can $6 for first-year relapse rates for the treatments.
  
  
  CONCLUSIONS
  Based on the current available clinical evidence, this model analysis of hypothetical patients suggests that IVIg may not be a cost-effective option for adults with persistent chronic ITP in Canada.
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada. fengxie@mcmaster.ca
authors.forename: Feng
authors.initials: F
authors.lastname: Xie
authors.forename: Gord
authors.initials: G
authors.lastname: Blackhouse
authors.forename: Nazila
authors.initials: N
authors.lastname: Assasi
authors.forename: Kaitryn
authors.initials: K
authors.lastname: Campbell
authors.forename: Mitchell
authors.initials: M
authors.lastname: Levin
authors.forename: Jim
authors.initials: J
authors.lastname: Bowen
authors.forename: Jean-Eric
authors.initials: JE
authors.lastname: Tarride
authors.forename: David
authors.initials: D
authors.lastname: Pi
authors.forename: Ron
authors.initials: R
authors.lastname: Goeree
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use; D002170:Canada; D002908:Chronic Disease; D003362:Cost-Benefit Analysis / Q000379:methods / Q000706:statistics & numerical data; D003661:Decision Support Techniques; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use*; D008875:Middle Aged; D018803:Models, Economic; D011241:Prednisone / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use; D011696:Purpura, Thrombocytopenic / Q000188:drug therapy* / Q000191:economics*; D019057:Quality-Adjusted Life Years; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D000893:Anti-Inflammatory Agents; D016756:Immunoglobulins, Intravenous; D011241:Prednisone