BackgroundHospital discharge is a vulnerable stage in the patient pathway. Research highlights communication failures and the problems of co-ordination as resulting in delayed, poorly timed and unsafe discharges. The complexity of hospital discharge exemplifies the threats to patient safety found ‘between’ care processes and organisations. In developing this perspective, safe discharge is seen as relying upon enhanced knowledge sharing and collaboration between stakeholders, which can mitigate system complexity and promote safety.AimTo identify interventions and practices that support knowledge sharing and collaboration in the processes of discharge planning and care transition.SettingThe study was undertaken between 2011 and 2013 in two English health-care systems, each comprising an acute health-care provider, community and primary care providers, local authority social services and social care agencies. The study sites were selected to reflect known variations in local population demographics as well as in the size and composition of the care systems. The study compared the experiences of stroke and hip fracture patients as exemplars of acute care with complex discharge pathways.DesignThe study involved in-depth ethnographic research in the two sites. This combined (a) over 180 hours of observations of discharge processes and knowledge-sharing activities in various care settings; (b) focused ‘patient tracking’ to trace and understand discharge activities across the entire patient journey; and (c) qualitative interviews with 169 individuals working in health, social and voluntary care sectors.FindingsThe study reinforces the view of hospital discharge as a complex system involving dynamic and multidirectional patterns of knowledge sharing between multiple groups. The study shows that discharge planning and care transitions develop through a series of linked ‘situations’ or opportunities for knowledge sharing. It also shows variations in these situations, in terms of the range of actors, forms of knowledge shared, and media and resources used, and the wider culture and organisation of discharge. The study also describes the threats to patient safety associated with hospital discharge, as perceived by participants and stakeholders. These related to falls, medicines, infection, clinical procedures, equipment, timing and scheduling of discharge, and communication. Each of these identified risks are analysed and explained with reference to the observed patterns of knowledge sharing to elaborate how variations in knowledge sharing can hinder or promote safe discharge.ConclusionsThe study supports the view of hospital discharge as a complex system involving tightly coupled and interdependent patterns of interaction between multiple health and social care agencies. Knowledge sharing can help to mitigate system complexity through supporting collaboration and co-ordination. The study suggests four areas of change that might enhance knowledge sharing, reduce system complexity and promote safety. First, knowledge brokers in the form of discharge co-ordinators can facilitate knowledge sharing and co-ordination; second, colocation and functional proximity of stakeholders can support knowledge sharing and mutual appreciation and alignment of divergent practices; third, local cultures should prioritise and value collaboration; and finally, organisational resources, procedures and leadership should be aligned to fostering knowledge sharing and collaborative working. These learning points provide insight for future interventions to enhance discharge planning and care transition. Future research might consider the implementation of interviews to mediate system complexity through fostering enhanced knowledge sharing across occupational and organisational boundaries. Research might also consider in more detail the underlying complexity of both health and social care systems and how opportunities for knowledge sharing might be engendered to promote patient safety in other areas.FundingThe National Institute for Health Research Health Services and Delivery Research programme.