Prevalence and correlates of antipsychotic polypharmacy in Hong Kong

Antipsychotic polypharmacy (APP) remains a common practice despite inconclusive empirical evidence of additional efficacy and potential exacerbation of side effects. Previous studies suggest APP rate is notably high in East Asia. This paper aims to investigate the prevalence and correlates of APP in Hong Kong.

This was a cross-sectional study of 728 patients with psychosis. The demographics and clinical information, including age, gender, diagnosis, hospitalization history, and medication were collected. Chi-square tests and logistic regression analyses were used to study correlates of APP.

The APP rate for psychosis was 24.2% (n = 728) and that for schizophrenia was 26.0% (n = 611), both considerably lower than our previous local data and that from East Asian regions. The most widely used APP prescription fell within the atypical/atypical combination (i.e., Amisulpride/Clozapine and Paliperidone/Olanzapine), and Olanzapine was the most commonly prescribed antipsychotic. At least 75% of APP patients with psychosis took at least one type of atypical antipsychotics in their medical regimen. Typical/typical polypharmacy was associated with older age and use of antiparkinson drugs. Typical/atypical polypharmacy was associated with the use of antiparkinson drugs and anxiolytics, as well as inpatient status. Atypical/atypical polypharmacy was associated with younger age, inpatient status, and the use of mood stabilizers.

Overall, our study highlights a relatively low APP rate in Hong Kong when compared to other countries in East Asia. Age, inpatient status and use of antiparkinson drugs, anxiolytics and mood stabilizers were associated with use of APP.