Predictive models to estimate utility from clinical questionnaires in ă schizophrenia: findings from EuroSC
Résumé
The clinical symptoms of schizophrenia are associated with serious ă social, quality of life and functioning alterations. Typically, data on ă health utilities are not available in clinical studies in schizophrenia. ă This makes the economic evaluation of schizophrenia treatments ă challenging. The purpose of this article was to provide a mapping ă function to predict unobserved utility values in patients with ă schizophrenia from the available clinical and socio-demographic ă information. ă The analysis was performed using data from EuroSC, a 2-year, ă multi-centre, cohort study conducted in France (N = 288), Germany (N = ă 618), and the UK (N = 302), totalling 1208 patients. Utility was ă calculated based on the EQ-5D questionnaire. The relationships between ă the utility values and the patients' socio-demographic and clinical ă characteristics (Positive and Negative Syndrome Scale-PANSS, Calgary ă Depression Scale for Schizophrenia-CDSS, Global Assessment of ă Functioning-GAF, extra-pyramidal symptoms measured by Barnes Akathisia ă Scale-BAS, age, sex, country, antipsychotic type) were modelled using a ă random and a fixed individual effects panel linear model. ă The analysis demonstrated the prediction ability of the used parameters ă for estimating utility measures in patients with schizophrenia. Although ă there are small variations between countries, the same variables appear ă to be the key predictors. From a clinical perspective, age, gender, ă psychopathology, and depression were the most important predictors ă associated with the EQ-5D. ă This paper proposed a reliable, robust and easy-to-apply mapping method ă to estimate EQ-5D utilities based on demographic and clinical measures ă in schizophrenia.