A retrospective observational study of the effectiveness of paliperidone palmitate on acute inpatient hospitalization rates.

This retrospective mirror-image observational study aimed to establish the effects of the long-acting antipsychotic injection paliperidone palmitate (PP) on acute inpatient hospitalization rates. We utilized routinely collected clinical data to compare the number and length of acute patient admissions 1 year before and 1 year after initiation of PP. A single cohort of 66 patients with a diagnosis of schizophrenia and who had received monthly injections of PP for at least 1 year were included in the analysis. The mean number of acute inpatient admissions fell from 0.86 in the year before PP initiation to 0.23 in the following year (P = 0.001), and there was a numerical but nonsignificant decrease in the number of bed days from 32.48 to 31.22 over the study duration. The median number of bed days in the year before PP initiation was 20, and in the year after initiation it was 0. The median number of admissions also fell from 1 to 0 during the same period. The results of the study should be treated cautiously because of the limitations of the study design but suggest that patients with a diagnosis of schizophrenia who continue treatment with PP over 12 months experience a significant reduction in hospital admissions compared with the previous year.