Combination of Clozapine With Long-Acting Injectable Antipsychotics in Treatment-Resistant Schizophrenia: Preliminary Evidence From Health Care Utilization Indices



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Background: Clozapine is indicated for treatment-resistant schizophrenia (TRS), but only 30%–60% of patients will respond. There have been studies of clozapine augmentation with oral second-generation antipsychotics with mixed results, but no studies considering the combination with long-acting injectable antipsychotics (LAIAs). This study is the first to attempt to establish the benefits of the combination of clozapine and LAIAs in TRS using a variety of outcome measures of symptomatology and quality of life.

Methods: A mirror-image study design was employed to review outcome measures 2 years pre and post combination of clozapine with a LAIA in a small sample of patients with chronic schizophrenia or schizoaffective disorders followed by the assertive community treatment service in the community. Outcome measures include demographic data, Brief Psychiatric Rating Scale, Clinical Global Impressions Scale–Improvement and Severity, 24-item Behavior and Symptom Identification Scale, World Health Organization Quality of Life Scale, Health of the Nation Outcome Scales, Threshold Assessment Grid, number of admissions, emergency department (ED) visits, and hospital bed days.

Results: Paired sample t tests showed a statistically significant reduction in average ED visits and hospital admissions in the 2 years post combination, with an average 1.8 fewer ED visits (95% CI, 0.58–3.02, P = .024) and a mean reduction of 0.85 hospital admissions (95% CI , 0.363–1.337, P = .008). The reduction in hospital bed days post combination was not statistically significant. Chart reviews found insufficient data for analysis of the remaining outcome measures.

Conclusions: The combination of clozapine and a long-acting injectable antipsychotic appears to reduce health care utilization in terms of ED visits and number of hospital admissions. Larger prospective studies will be required to confirm the results.

Prim Care Companion CNS Disord 2020;22(4):19m02560