Cost-effectiveness analysis of schizophrenia relapse prevention : an economic evaluation of the ZEUS (Ziprasidone-Extended-Use-In-Schizophrenia) study in Spain.
OBJECTIVE
The aim of this study was to estimate the cost-effectiveness of schizophrenia relapse prevention in Spain using data from the ZEUS (Ziprasidone-Extended-Use-in-Schizophrenia) study.


METHODS
Treatment of schizophrenia was modeled over 1 year using a retrospective deterministic model from the Spanish National Health System (NHS) perspective (year 2005). The primary outcome was the probability of relapse occurring within a 52-week period of treatment with daily doses of ziprasidone 40-160mg versus placebo. Data were obtained from a randomised, double-blind clinical trial (n = 218 patients). Antipsychotic cost, concomitant medications to treat adverse events (for example extrapyramidal symptoms) and medical costs associated with adverse events were derived from the clinical trial results and a Spanish health cost database. The average cost of a relapse admitted to hospital in Spain (3421 euro) was obtained from a retrospective study.


RESULTS
The probability of psychosis relapse was 0.77 with placebo, and 0.43, 0.35, 0.36 and 0.38 with ziprasidone daily doses of 40, 80, 160mg and average dose, respectively (p < 0.01 vs placebo in all cases). The average annual incremental cost per relapse avoided was 186 euro for the average dose, ranging from a saving of 557 euro (80 mg/day) to an incremental cost of 1015 euro (160 mg/day), and was lower in all cases than the minimum cost of a relapse (2830 euro).


CONCLUSIONS
According to this evaluation, psychosis relapse prevention with ziprasidone is cost effective compared with no treatment from the Spanish NHS perspective. Ziprasidone therapy avoids a considerable number of relapses at a reasonable cost, producing cost savings.
Bernardo
Miguel
M
Department of Psychiatry, Hospital Clinic i Provincial, Barcelona, Spain.
Ramón Azanza
Jose
J
Rubio-Terrés
Carlos
C
Rejas
Javier
J
D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use; D002908:Chronic Disease; D003362:Cost-Benefit Analysis / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D006801:Humans; D017059:Models, Econometric; D010879:Piperazines / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D015397:Program Evaluation / Q000379:methods; D012008:Recurrence; D015203:Reproducibility of Results; D012559:Schizophrenia / Q000191:economics / Q000517:prevention & control*; D013030:Spain; D013844:Thiazoles / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D013997:Time Factors
D014150:Antipsychotic Agents; D010879:Piperazines; D013844:Thiazoles; C092292:ziprasidone