One-year treatment continuation in patients prescribed risperidone long-acting injection in New Zealand: a retrospective study.

OBJECTIVE Treatment discontinuation is a major problem in routine clinical settings and is associated with poorer outcomes for conditions like schizophrenia. Risperidone long-acting injection (RLAI) has shown low discontinuation and good tolerability in long-term clinical trials. This retrospective study investigated RLAI continuation in a naturalistic clinical setting in New Zealand. METHODS Those starting publicly funded RLAI between October 1, 2005 and October 31, 2006 in five public mental health services were included in the study. Data were retrospectively collected for 443 patients 12 months pre- and post-RLAI initiation. Patient demographics, diagnosis, antipsychotic treatment and treatment setting were obtained from clinical files and patient information systems. RESULTS Patients were mostly male (64%), the mean age was 35.9 years, and were predominantly European (43%) or Māori (29%). Most started RLAI due to adherence issues (77%). Adverse events due to RLAI were reported by 39%; most commonly, extrapyramidal side effects. Fifty-eight percent of patients continued treatment 12 months after starting; patient choice (either refusal or failure to turn up) was the most common reason for discontinuation (54%), followed by lack of efficacy (29%). Alternative antipsychotic treatment was prescribed for 79% of those who discontinued. Regression analysis found continuation was more common for people started in the community, on a compulsory treatment order, with a dose of >25 mg and for non-Māori. CONCLUSIONS RLAI appears well-tolerated and over half the patients continued treatment for one year or more. Using treatment continuation as an indicator of effectiveness, RLAI appears to be an effective treatment for people with adherence problems in this real world practice setting.