Rehospitalisation rates after long-term follow-up of patients with severe mental illness admitted for more than one year: a systematic review

AIMS: This study aimed to conduct a systematic review of studies on the outcomes of long-term hospitalisation of individuals with severe mental illness, considering readmission rates as the primary outcome. METHODS: Studies considered were those in which participants were aged between 18 and 64 years with severe mental illness; exposure to psychiatric hospitals or wards was long-term (more than one year); primary outcomes were readmission rates; secondary outcomes were duration of readmission, employment, schooling, and social participation; and the study design was either observational or interventional with a randomised controlled trial (RCT) design. Relevant studies were searched using MEDLINE, PsycINFO, Web of Science, CINAHL, and the Japan Medical Abstract Society. The final search was conducted on 1 February 2022. The risk of bias in non-randomised studies of interventions was used to assess the methodological quality. A descriptive literature review is also conducted. RESULTS: Of the 11,999 studies initially searched, three cohort studies (2,293 participants) met the eligibility criteria. The risk of bias in these studies was rated as critical or serious. The 1–10 years readmission rate for patients with schizophrenia who had been hospitalised for more than one year ranged from 33 to 55%. The average of readmission durations described in the two studies was 70.5 ± 95.6 days per year (in the case of a 7.5-year follow-up) and 306 ± 399 days (in the case of a 3–8-year follow-up). None of the studies reported other outcomes defined in this study. CONCLUSIONS: The readmission rates in the included studies varied. Differences in the follow-up period or the intensity of community services may have contributed to this variability. In countries preparing to implement de-institutionalisation, highly individualised community support should be designed to avoid relocation to residential services under supervision. The length of stay for readmissions was shorter than that for index admissions. The results also imply that discharge to the community contributes to improved clinical outcomes such as improved social functioning. The validity of retaining patients admitted because of the risk of rehospitalisation was considered low. Future research directions have also been discussed. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-023-05290-x.