(232) Disease relapse, adverse events and all-cause mortality associated with the use of long-acting injectable antipsychotics versus oral antipsychotics in older people with schizophrenia: a self-controlled case series study

Publication Number: 565

Background: The clinical evidence on long-acting injectable antipsychotics (LAIAs) versus oral antipsychotics (OAs) has not been well established in Asian populations and special patient groups.

Objectives: To compare the risk of disease relapse, healthcare utilization, and adverse events between the use of LAIAs and OAs among patients 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 patients diagnosed with schizophrenia and prescribed LAIAs and OAs during 2004-2019. Differences in the risk of disease relapse (hospitalizations for psychiatric disorders and for schizophrenia and incident suicide attempt), healthcare utilization (hospitalizations and emergency department [ED] visits), and adverse events (extrapyramidal symptoms [EPS] and hospitalizations for somatic disorders and for cardiovascular diseases) between LAIAs and OAs were assessed using Poisson regression.

Results: Of the 70,396 patients with schizophrenia, 23,719 were prescribed LAIAs and OAs during the study period. Compared with OAs, LAIAs were associated with a lower risk of hospitalization for any reason (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 incident 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 events (IRR=0.86 [0.82-0.91]). No significant difference was found in the risk of ED visits (IRR=0.99 [0.97-1.00]). Similar associations were observed during the subsequent treatment period (90 days afterwards), and in the elderly and patients with substance use, except that the use of LAIAs was associated with an increased risk of EPS in the elderly.

Conclusions: LAIAs were associated with a lower risk of disease relapses and hospitalizations than OAs, without increasing the risk of adverse events. The findings also suggested the use of LAIAs in patients with substance use, while the potential for EPS should be closely monitored in the elderly. Generally, our findings support expending the utilization of LAIAs in Chinese patients with schizophrenia.