Introduction: In the northwest of the Netherlands, health and social care professionals have sought to structure and coordinate care and support for older people living at home with multiple health and social care needs. The region was selected as one of the case sites of a European project called SUSTAIN, which aimed to facilitate and evaluate improvements to established integrated care initiatives for older people living at home. By participating in the SUSTAIN project, local stakeholders collaborated with researchers to further improve their way of working. This case study describes the process and outcomes of the development and implementation of improvements, as well as the factors that influenced this improvement process. Insight into this process may provide valuable lessons that could be transferable to other integrated care initiatives Methods: Using a participatory approach, guided by the Evidence Integration Triangle (Glasgow, 2012), local stakeholders defined and implemented a tailored intervention aimed at improving collaboration and communication between health and social care professionals. Researchers monitored and evaluated this improvement process. Multiple data sources were used, including the Team Climate Inventory (n=11), interviews with managers and professionals delivering health and social care (n=8), meeting minutes (n=10) and field notes. Results and Discussion: The tailored intervention consisted of regular intervision meetings (i.e. meetings consisting of peer supervision and methodical discussion to reflect on professional development) as well as workplace visits. According to professionals, the intervention resulted in improved communication and collaboration. Facilitating factors included the safe and informal setting in which the meetings took place and the personal relationships that developed during the project. Managers also valued the intervention, although they voiced concerns about the scale and sustainability of the implementation. Issues such as staff shortages, time ...