Clinical Psychopharmacology and Neuroscience 2019; 17(4): 531-536  
The Impact of Paliperidone Palmitate on Hospitalization in Patients with Schizophrenia: A Retrospective Mirror-image Study
So-Young Oh1, Duk-In Jon1, Hyun Ju Hong1, Narei Hong1, Jung-Seo Yi2, Daeyoung Roh3, Myung Hun Jung1
1Department of Psychiatry, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, 2Department of Psychiatry, Hallym University Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, 3Mind-neuromodulation Laboratory and Department of Psychiatry, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, Chuncheon, Korea
Correspondence to: Myung Hun Jung
Department of Psychiatry, Hallym University Sacred Heart Hospital, 22 Gwanpyeong-ro 170beon-gil, Dongan-gu, Anyang 14068, Korea
Received: May 7, 2019; Revised: June 18, 2019; Accepted: June 19, 2019; Published online: November 30, 2019.
© The Korean College of Neuropsychopharmacology. All rights reserved.

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Objective: Whether long-acting injectable antipsychotics (LAI) are superior to oral antipsychotics remains a controversial question, and results vary depending on the study design. Our study was performed to compare outcomes of oral antipsychotics and paliperidone palmitate (PP) in clinical practice by investigating the numbers of admissions and bed days.
Methods: We performed a retrospective observational mirror-image study at a single medical center, reviewing medical charts to obtain the clinical data. Forty-six patients with a diagnosis of schizophrenia or schizoaffective disorder who had received at least two doses of PP were included in the analysis. The Wilcoxon signed-rank test was used to compare the numbers of bed days and admissions 1 year before starting PP with those numbers at 1 year after.
Results: The mean number of admissions fell from 0.83 to 0.17 per patient (p < 0.0002), and the median fell from 1 to 0. The mean number of bed days decreased significantly, from 24.85 to 8.74 days (p < 0.006). The outcomes remained similar in sensitivity analyses set up with different mirror points.
Conclusion: Our results indicate that initiating PP reduced the mean numbers of hospital admissions and bed days compared with prior oral medication. LAIs may thus be cost effective in practice; its use bringing about cost reductions greater than its purchase cost.
Keywords: Schizophrenia; Paliperidone palmitate; Mirror-image study; Number of admissions; Number of bed days; Sensitivity analyses.

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