BACKGROUND:
The World Health Organization’s Framework on Integrated, People-Centred Health Services (IPCHS) proposes five interdependent strategies to guide health system transformation. In low- and middle-income countries (LMICs), implementation of IPCHS is often fragmented due to limited understanding of how its strategies interact in practice. This study aimed to reconceptualise how IPCHS strategies interact in practice by identifying the underlying mechanisms that enable or constrain people-centred care, using CHW performance as an analytical entry point.

METHODS:
This study used a multi-phase realist approach, which focuses on understanding what works, for whom, and under what conditions, integrating a realist synthesis and two realist evaluations in KwaZulu-Natal, South Africa. Findings from each phase contributed to refining an initial programme theory into a dynamic, mechanism-sensitive model that captures how IPCHS strategies function interdependently. Data were analysed using context–mechanism–outcome (CMO) configurations. Systems thinking tools, including causal loop diagrams, were used to visualise mechanism chaining and feedback loops across system levels and strategies.

RESULTS:
Three cross-cutting meta-mechanisms: trust, motivation, and professional legitimacy (with institutional support) were found to underpin CHW performance across all five IPCHS strategies. These mechanisms interacted recursively, meaning activation or erosion of one affected others. People-centred care is not the outcome of any single strategy but rather emerges from the alignment and interaction of mechanisms triggered by multiple strategies in different contexts. When mechanisms align, they reinforce CHW performance and advance IPCHS; when misaligned, they contribute to system fragility and poor outcomes.

CONCLUSIONS:
People-centred care is an emergent property of aligned, interacting IPCHS strategies, as opposed to isolated interventions. The proposed mechanism-sensitive model provides policymakers and implementers with a practical approach to move beyond fragmented reforms towards a more coherent, people-centred health system transformation. Further research should test and refine the proposed mechanism-sensitive approach to implementing the IPCHS framework.