Real-World Utilization Patterns of Long-Acting Injectable Antipsychotics in Canada: A Retrospective Study

Objective: The objective of this study was to analyze the real-world prevalence of long-acting injectable (LAI) antipsychotic use and determine when LAIs are being used in sequencing of antipsychotic medications among Canadian patients with schizophrenia. Methods: This was a retrospective, longitudinal cohort study using Canadian pharmacy prescription data between August 2005 and June 2017. Patients with inferred schizophrenia spectrum disorder were indexed on the date of their first antipsychotic prescription and analyzed for minimum 12 months to track lines of antipsychotic therapy and LAI utilization. Results: A total of 16,300 patients were identified for analysis. 48.2% and 46.0% of index antipsychotic prescriptions were prescribed by a general practitioner/family medicine doctor and psychiatrist, respectively. 1,062 (6.5%) patients used an LAI during the study period. Of those patients, 789 used an LAI within two years of index (74.3% of LAI users; 4.8% of all patients). The majority of LAI use (62.0%) occurred in the third line of therapy or later. 65.0% of patients had tried at least two therapy lines, and most patients reported gaps of six months to one year between treatment lines. Conclusion: Despite their potential to reduce relapse in schizophrenia by improving treatment adherence, this study shows LAIs continue to be under-utilized in Canada. When used, LAIs are positioned late in sequencing of antipsychotic medications, often not initiated until years after diagnosis. Continued preference for oral APs with poor adherence may be negatively impacting prognosis and exacerbating burden of schizophrenia. Efforts should be invested to understand barriers to LAI uptake and advocate for earlier, widespread use of LAIs.