OBJECTIVES

Utility elicitation studies for states of schizophrenia generate different utility values. We reviewed utility values used in schizophrenia pharmacoeconomic evaluations and evaluated the impact of their selection on the incremental cost-effectiveness ratio (ICER).

METHODS

A systematic search was performed in Medline and Embase. Health state definitions, associated utility values, elicitation studies, and value selection processes were extracted. Sets of utility values for all states of schizophrenia were used in a cost-effectiveness model to evaluate the ICER

RESULTS

Thirty-five cost-utility analyses (CUAs) referring to 11 utility elicitation studies were included. The most frequent health states were “stable” (28 CUAs, 7 utility elicitation studies, 10 utility values, value range 0.650-0.919), “relapse requiring hospitalisation” (18, 5, 7, 0.270-0.604), “relapse not requiring hospitalisation” (18, 5, 10, 0.460-0.762), and “relapse only” (10, 5, 6, 0.498-0.700). Most CUAs (n=27) derived utility values for all states of schizophrenia from a single utility elicitation study, while 8 used multiple sources. In total, 11 utility elicitation studies were referred, generating 17 sets of utility values of schizophrenia states. Three utility elicitation studies were referred to >1 sets of utility values, differing in the classification of the states of schizophrenia, the interpretation of the states from the utility elicitation study into the state used in the model, and the analytical approach. One group of utility elicitation studies was referred to 2 sets of utility values, differing in the selection of utility elicitation studies for one state of schizophrenia. The 17 sets of utility values were applied in the cost-effectiveness model, and generated an ICER ranging from -56.2% to +222.6% from average ICER.

CONCLUSIONS

The use of utility values for states of schizophrenia differs among CUAs and impacts on the ICER. More rigorous and transparent use of utility values is suggested for future CUAs in schizophrenia.