Effect of 3-monthly paliperidone palmitate on hospitalisation in a naturalistic schizophrenia cohort – A five-year mirror image study

Currently the longest-acting antipsychotic formulation widespread clinical use is paliperidone 3-monthly injection (PP3M). While its efficacy has been shown in rigorous trials, there are few data relating to its effect on hospitalisation in normal clinical practice. This was a mirror-image study (3 years before; 2 years after) of hospitalisations before and after beginning paliperidone 1-monthly (PP1M) and switching to 3-monthly within 18 months. All consecutive patients prescribed paliperidone long-acting injections with its licence (F20 schizophrenia diagnosis; 18–65 years) were included. The setting was an urban, specialist mental health organisation In London, UK. In total 378 patients were initiated on PP3M during the study period. After applying inclusion criteria, 76 patients were retained and followed-up for 2 years. Mean duration of PP1M use before starting 3-monthly injections was 6 months (range 3–18 months). Of the 76 patients initiated, 13 patients discontinued PP3M within 2 years of starting PP1M or were lost to follow-up. Mean hospitalisations per patient per year fell from 0.55 (SD 0.46) before paliperidone to 0.05 (SD 0.19) after initiation (p < 0.001). Only 5 of 76 PP1M/PP3M participants were hospitalised during the 2-year follow up. The mean number of bed days per year before paliperidone initiation was 32.2 (SD 44.3) and after paliperidone initiation it was 23.0 (SD 53.2) (p = 0.004). Almost all of the bed days after initiation were associated with the index admission during which PP1M was started. In patients stabilised on PP1M and switched to PP3M in normal clinical practice, rehospitalisation is very uncommon and much reduced compared with previous treatments.