Medication Gaps and Antipsychotic Polypharmacy in Previously Hospitalized Schizophrenia Patients: An Electronic Cohort Study in Three Canadian Provinces

Evyn Peters; Arash Shamloo; Rohit J Lodhi; Gene Marcoux; Kylie Jackson; Shawn Halayka; Lloyd Balbuena

doi:10.3389/fpsyt.2022.917361

Medication Gaps and Antipsychotic Polypharmacy in Previously Hospitalized Schizophrenia Patients: An Electronic Cohort Study in Three Canadian Provinces

Front Psychiatry. 2022 Jun 15:13:917361. doi: 10.3389/fpsyt.2022.917361. eCollection 2022.

Authors

Evyn Peters¹, Arash Shamloo¹, Rohit J Lodhi², Gene Marcoux¹, Kylie Jackson³, Shawn Halayka⁴, Lloyd Balbuena¹

Affiliations

¹ Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada.
² Department of Psychiatry, University of Western Ontario, London, ON, Canada.
³ Mental Health Outpatient Services, Saskatchewan Health Authority, Prince Albert, SK, Canada.
⁴ Independent Researcher, Prince Albert, SK, Canada.

Abstract

Background: Real world evidence about antipsychotics focuses on rehospitalization. Modeling the time course of pharmacotherapy would show patients' adherence to medications and physicians' adherence to medication guidelines. We aimed to calculate the cumulative time spent in second generation antipsychotics (SGAs), gaps, antipsychotic polypharmacy, and clozapine in discharged schizophrenia patients.

Methods: Hospitalization and pharmacy dispensing data from 2008-2018 in Manitoba, Saskatchewan, and British Columbia were linked and an electronic cohort (N = 2,997) was created (mean follow-up: 49 months, SD = 38). Cohort members were required to have a minimum of 6 weeks medicated with aripiprazole, olanzapine, paliperidone, quetiapine, risperidone, or ziprasidone.

Results: The multistate model predicted that schizophrenia patients accumulated 44 months in SGA monotherapy, 4 months in polypharmacy, 11 months in medication gaps and 17 days in clozapine over a 5-year period. The majority of transitions were between SGA and medication gap. Accumulated time in medication gaps was seven times as much as in clozapine. Each 10% delay in SGA initiation post-discharge was associated with a 2, 1, and 6% higher risk for polypharmacy (95% CI: 1.01-1.02), gap (95% CI: 1.01-1.01), and clozapine (95% CI: 1.04-1.08), respectively.

Interpretation: Schizophrenia patients accumulated more time unmedicated and in polypharmacy compared to clozapine. Either treatment guidelines for schizophrenia are not followed, or real-world challenges hamper their implementation.

Keywords: adherence - compliance - persistance; antipsychotics; polypharmacy; real world evidence (RWE); schizophenia; treatment guideline implementation.