(76) Disease Relapse, Healthcare Utilization and Adverse Events Associated with The Use of Long-Acting Injectable Antipsychotics Versus Oral Antipsychotics in People with Schizophrenia: A Self-Controlled Case Series Study

Publication Number: 750

Background: Evidence for improved clinical outcomes with long-acting injectable antipsychotics (LAIAs) versus oral antipsychotics (OAs) is limited in Asian populations with schizophrenia and special patient groups.

Objectives: To compare the risk of disease relapse, healthcare utilization, and adverse events associated with LAIAs and OAs among people with schizophrenia in Hong Kong.

Methods: In this population-based self-controlled case series study, we used the electronic medical record database of the Hong Kong Clinical Data Analysis and Reporting System (CDARS) to identify people diagnosed with schizophrenia (International Classification of Diseases-9th Revision 295) and prescribed LAIAs and OAs during 2004-2019. Risk of disease relapse (hospitalizations for psychiatric disorders and for schizophrenia, and incident suicide attempt), healthcare utilization (all-cause hospitalizations and emergency department [ED] visits), and adverse events (somatic hospitalizations, cardiovascular hospitalizations and extrapyramidal symptoms [EPS]) between the full treatment periods of LAIAs alone and OAs alone were compared using Poisson regression by adjusting for age and season. The risk during the subsequent treatment periods (beyond the first 90 days in each treatment) of LAIAs alone and OAs alone, in older people (>65 years) and people with substance use were further evaluated.

Results: Of the 70,396 individuals with schizophrenia, 23,719 were prescribed LAIAs and OAs during the observation period. Compared with OAs, LAIAs were associated with a lower risk of hospitalization for any cause (incidence rate ratio [IRR]=0.63 [95% CI 0.61-0.65]), psychiatric disorders (IRR=0.52 [0.50-0.53]) and schizophrenia (IRR=0.53 [0.51-0.55]), and suicide attempt (IRR=0.56 [0.44-0.71]). There was also a reduction in somatic hospitalizations (IRR=0.88 [0.85-0.91]), cardiovascular hospitalizations (IRR=0.88 [0.81-0.96]) and EPS (IRR=0.86 [0.82-0.91]). No significant difference was found for ED visits (IRR=0.99 [0.97-1.00]). Similar associations were observed during the subsequent treatment period, and in older people and people with substance use, except for the increased risk of EPS (IRR=1.38 [1.13-1.67]) associated with LAIAs in older people.

Conclusions: Overall, LAIAs were associated with a lower risk of disease relapse and hospitalization than OAs, without an increased risk of adverse events. Clinicians should more broadly consider the long-term use of LAIAs in Chinese people with schizophrenia while the potential for EPS should be closely monitored in older people.