title: Cost-effectiveness of clozapine monitoring after the first 6 months.
abstract: BACKGROUND
  Clozapine is effective in treating patients with schizophrenia who do not respond to conventional neuroleptic drugs. The drug is unique in that it is available only with a US Food and Drug Administration-mandated system for weekly monitoring of patients' white blood cell counts. No study has been conducted to evaluate the cost-effectiveness of this mandatory monitoring system.
  
  
  METHODS
  A benchmark case was established by utilizing cumulative incidence rates of agranulocytosis from a recent study with a large sample of clozapine-treated patients. We assumed a 20% mortality among patients with agranulocytosis, $30.61 in monitoring costs each week, and 14.4 years of remaining life expectancy after detection of agranulocytosis. Based on these bench-mark assumptions, cost-effectiveness ratios in dollars per quality-adjusted life-year were calculated for the first, second, and third 6-month periods during which a patient was receiving clozapine. Sensitivity analyses were performed with more conservative assumptions in 5 alternative scenarios.
  
  
  RESULTS
  In the benchmark case, costs per quality-adjusted life-year gained were $61,694, $925,418, and $420,644 for the first, second, and third 6-month periods of clozapine treatment, respectively. In the alternative scenarios, these costs ranged from $7923 to $46,056 for the first 6-month period and from $54,025 to $690,850 for the second and third 6-month periods.
  
  
  CONCLUSIONS
  While the costs of monitoring patients with schizophrenia in the first 6-month period of clozapine treatment seem to be justifiable, monitoring thereafter may not be cost-effective because of the very low incidence of agranulocytosis in the later periods.
authors.affiliation: Veterans Affairs Health Services Research and Development Field Program, Veterans Affairs Medical Center, Little Rock, Ark, USA.
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: R R
authors.initials: RR
authors.lastname: Owen
authors.forename: S K
authors.initials: SK
authors.lastname: Pope
authors.forename: G R
authors.initials: GR
authors.lastname: Smith
mesh_terms: D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems / Q000191:economics*; D017668:Age of Onset; D000380:Agranulocytosis / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality; D003024:Clozapine / Q000009:adverse effects* / Q000191:economics / Q000627:therapeutic use*; D003362:Cost-Benefit Analysis; D016527:Drug Costs; D016903:Drug Monitoring / Q000191:economics*; D006801:Humans; D015994:Incidence; D007958:Leukocyte Count / Q000191:economics; D008875:Middle Aged; D019057:Quality-Adjusted Life Years; D012559:Schizophrenia / Q000097:blood / Q000188:drug therapy* / Q000191:economics
chemical_list: D003024:Clozapine