Pattern of use of clozapine in Spain. Variability and under-prescription

International studies on clozapine use usually show lower than expected prescription proportions, under-dosing and delayed initiation of treatment, which has led to a number of initiatives aimed at improving its use and reducing the striking variability observed among practitioners. There are no similar studies on the Spanish population. Therefore we planned initial data collection from 4 territorial samples. We hypothesized that clozapine prescription would also be low and variable in our country. If this hypothesis were confirmed, a reflection on possible strategies would be necessary.

We accessed data on clozapine prescription in Catalonia, Castile and Leon, the Basque Country and the Clinical Management Area of the Hospital 12 de Octubre (Madrid).

Patients diagnosed with schizophrenia under treatment in these territories comprise around .3% of their total population; treatment with clozapine ranges between 33.0 and 57.0 per 10000 inhabitants; patients diagnosed with schizophrenia on current treatment with clozapine range between 13.7% and 18.6% of the total number of patients with this diagnosis. The coefficient of variation between centres and prescribers is often higher than 50%.

Although below the figures suggested as desirable in the literature, global prescribing data for clozapine in the areas we studied are not as low as the data collected in other international studies, and are in the range of countries in our environment. However, the variability in prescription is large and apparently not justified; this heterogeneity increases as we focus on smaller areas, and there is great heterogeneity at the level of individual prescription.