Open Access

Linda Steyer, Christian Kortkamp, Christiane Müller, Britta Tetzlaff, Nina Fleischmann, Clarissa E. Weber, Martin Scherer, Anja Kühn, Anne-Marei Jarchow, Frederike Lüth, Sascha Köpke, Tim Friede, Hans-Helmut König, Eva Hummers, Indre Maurer, Katrin Balzer

• Background: To improve interprofessional collaboration between registered nurses (RNs) and general practitioners (GPs) for nursing home residents (NHRs), the interprof ACT intervention package was developed. This complex intervention includes six components (e.g., shared goal setting, standardized procedures for GPs’ nursing home visits) that can be locally adapted. The cluster‑randomized interprof ACT trial evaluates the effects of this intervention on the cumulative incidence of hospital admissions (primary outcome) and secondary outcomes (e.g., length of hospital stays, utilization of emergency care services, and quality of life) within 12 months. It also includes a process evaluation which is subject of this protocol. The objectives of this evaluation are to assess the implementation of the interprof ACT intervention package and downstream effects on nurse–physician collaboration as well as preconditions and prospects for successive implementation into routine care. Methods: This study uses a mixed methods triangulation design involving all 34 participating nursing homes (clusters). The quantitative part comprises paper‑based surveys among RNs, GPs, NHRs, and nursing home directors at baseline and 12 months. In the intervention group (17 clusters), data on the implementation of preplanned implementation strategies (training and supervision of nominated IPAVs, interprofessional kick‑off meetings) and local implementation activities will be recorded. Major outcome domains are the dose, reach and fidelity of the implementation of the intervention package, changes in interprofessional collaboration, and contextual factors. The qualitative part will be conducted in a subsample of 8 nursing homes (4 per study group) and includes repeated non‑participating observations and semistructured interviews on the interaction between involved health professionals and their work processes. Quantitative and qualitative data will be descriptively analyzed and then triangulated by means of joint displays and mixed methods informed regression models. Discussion: By integrating a variety of qualitative and quantitative data sources, this process evaluation will allow comprehensive assessment of the implementation of the interprof ACT intervention package, the changes induced in interprofessional collaboration, and the influence of contextual factors. These data will reveal expected and unexpected changes in the procedures of interprofessional care delivery and thus facilitate accurate conclusions for the further design of routine care services for NHRs.