Hospital Readmissions Among People Experiencing Homelessness: A Cohort Study of Linked Hospitalisation and Mortality Data in England for 3,222 Homeless Inpatients

Background: Homeless hospital inpatients are often discharged to unstable accommodation or the street, which may increase the risk of readmission. Methods: We conducted a cohort study of 3,222 homeless patients discharged alive from hospitals across England between 2013 and 2016, with mean 2.4 years of follow-up. A comparison group of housed patients living in deprived areas was matched 1:1 on age group, sex, hospital and year of discharge. Counts of emergency re-admissions, planned re-admissions and A&E visits post-discharge were derived from national hospital databases. We reported readmission risk and used negative binomial regression to estimate rate ratios. Findings: After adjusting for health at study baseline, homeless patients had 3.77 (95% CI 3.46-4.10) times the rate of emergency readmission, 0.71 (0.63-0.81) times the rate of planned readmission, and 3.76 (3.53-4.01) times the rate of AE p<0.001) times the rate of AE 0.73-1.06; p=0.140) or emergency re-admissions (1.08; 0.98-1.18; p=0.102). Interpretation: Homeless inpatients have high rates of emergency readmission use that are not explained by their health. This highlights the need for discharge arrangements that address health, housing and social care needs. Funding Statement: This study was supported by the National Institute for Health Research (NIHR) [Project number: 13/156/10 to HS & DR]. The authors also acknowledge the support from the Health Data Research (HDR) UK which receives its funding from HDR UK Ltd funded by the UK Medical Research Council, Engineering and Physical Sciences Research Council, Economic and Social Research Council, Department of Health and Social Care (England), Chief Scientist Office of the Scottish Government Health and Social Care Directorates, Health and Social Care Research and Development Division (Welsh Government), Public Health Agency (Northern Ireland), British Heart Foundation (BHF) and the Wellcome Trust. ACH’s salary is provided by Central and North West London NHS Community Trust. AS is funded by UCLH Foundation Trust. DL is funded by the NIHR [DRF-2018-11-ST2-016]. JN is part-funded by the National Institute for Health Research (NIHR) Biomedical Research Centre for Mental Health at South London and Maudsley NHS Foundation Trust and King's College London. RBl is supported by a UK Research and Innovation Fellowship funded by a grant from the Medical Research Council [MR/S003797/1]. SL is funded by NIHR [ICA-CDRF-2016-02-042]. RBy is supported the NIHR Applied Research Collaboration (ARC) South West Peninsula.. Declaration of Interests: NH is medical director, and ACH is a trustee of the Pathway: Healthcare for homeless people charity. AS is Clinical Lead and Manager for Find and Treat. All other authors declare no conflicts of interest. Ethics Approval Statement: Collection of patient identifiers and data linkage were performed without explicit consent from participants due to the complexities in retrospectively identifying and obtaining consent, and because we wanted to use existing secondary data to examine mortality in this group. We engaged with people who had experience of homelessness and most felt that studies such as this are acceptable without consent, providing adequate data security measures are in place and studies have regulatory and ethical approval. This research was undertaken following approval (reference 16/CAG/0021) from the Secretary of State for Health through the Confidentiality Advisory Group (CAG). The Health Research Authority Research Ethics Committee approved the study (REC 16/EE/0018). In addition, local R&D approvals were obtained prior to local data collection at each of the Homeless Hospital Discharge Fund sites. After data linkage, we destroyed personal identifying data and undertook all analyses using the anonymised dataset outlined previously and in Figure 1. All study data were stored on the UCL Data Safe Haven, which has been certified to the ISO:27001:2013 information security standard and conforms to the NHS Information Governance Toolkit.