Friday, Oct. 28
14:30 – 15:30 (N/A)
Meeting Room: Cedar (Mezzanine)
Sebastien Brodeur*, MD, MSc; Josiane Courteau, PhD; Alain Vanasse, MD; Mireille Courteau, MSc; Emmanuel Stip, MD, MSc; Marie-Josée Fleury, PhD; Alain Lesage, MD, MSc; Marie-France Demers, BPharm, MSc; Olivier Corbeil, PharmD, MSc; Laurent Béchard, PharmD, MSc; Maxime Huot-Lavoie, MSc; Marc-André Roy, MD, MSc
Supported by the Psychopharmacology Section
- Medical Expert
At the end of this session, participants will be able to: 1) Identify common reasons for nonprescription of clozapine; 2) Identify different groups of patients based on their antipsychotic adherence profile prior to clozapine initiation; and 3) Understand that prior poor adherence does not appear to justify avoiding clozapine treatment.
A significant proportion of psychiatrists (from 41% to 82%) mentioned prior nonadherence to antipsychotic (AP) treatment as a major barrier to the introduction of clozapine.
Objective: To determine if prior poor adherence before initiating clozapine predisposed to poor adherence to clozapine or to any APs after its initiation.
Method: This cohort study included 3,228 patients living in Quebec with a diagnosis of schizophrenia (SCZ) initiating oral clozapine (index date) between 2009 and 2016. Adherence to AP treatment was measured by the medication possession ratio (MPR) over a one-year period preceding and following the index date. Five groups of patients were formed based on their prior MPR level, and two dependent variables were defined after clozapine initiation (good adherence to any APs and to clozapine only). Along with multiple logistic regressions, State Sequence Analysis (SSA) was used to visualize AP use trajectories over time.
Results: SSA revealed instantly that AP adherence was significantly improved in all groups regardless of the level of prior adherence to AP treatment. On the other hand, logistic regression showed that poorer adherence level to APs before the index date was significantly associated with an increased risk of poor adherence to any AP treatment after the index date. However, most patients adhered to their treatment after initiating clozapine (>68% to clozapine and >84% to any antipsychotics).
Discussion: Although widely recognized by clinicians as a barrier preventing the use of clozapine, prior poor adherence does not appear to justify avoiding clozapine treatment.
- Howes OD, Vergunst F, Gee S, et al. Adherence to treatment guidelines in clinical practice: study of antipsychotic treatment prior to clozapine initiation. Br J Psychiatry 2012;201:481–5.
- Farooq S, Choudry A, Cohen D, et al. Barriers to using clozapine in treatment-resistant schizophrenia: systematic review. BJPsych Bull 2019;43(1):8–16.