Abstract
This article presents an adaptation of Program Theory framework designed to support the implementation and evaluation of interventions delivered by advanced practice nurses within Hospital at Home models. In response to increasing healthcare demands associated with aging populations and multimorbidity, this framework integrates three interrelated theories; Program Organizational, Service Utilization, and Impact theories to conceptualize and assess advanced practice nurse led care delivery in Hospital at Home settings. Organizational Theory outlines the structural and functional requirements for integrating advanced practice nurses into Hospital at Home, including role definition, interprofessional collaboration, governance structures, and resource allocation. It emphasizes ways to foster the autonomy of advanced practice nurses, supporting clinical decision-making, and ensuring infrastructure for coordinated care. Service Utilization Theory focuses on the determinants of access, acceptance, and appropriateness of care. It addresses mechanisms for patient referral, eligibility assessment, and care escalation, and highlights the importance of aligning patient needs with the expertise of advanced practice nurses. The adapted Impact Theory identifies causal pathways linking interventions delivered by advanced practice nurses, such as early assessment, individualized care planning, home visits, therapeutic education, and care coordination to patient and caregiver, for system-level outcomes. These outcomes include reduced hospital admissions and readmissions, fewer emergency department visits, lower nursing home placement rates, and improved functional status, quality of life, and patient satisfaction. The Program Theory framework also supports the evaluation of caregiver burden and the effectiveness of self-management support including health literacy. Applied in the context of a French-speaking canton in Switzerland, where Hospital at Home services remain underdeveloped and advanced practice nurses are not integrated into these services, this framework provides a structured and theory-driven approach to guide the operationalization and evaluation of their interventions. It establishes a basis for the measurement of outcomes across care processes, individual experiences, and health system impacts. By aligning intervention components with expected outcomes, this approach addresses the complexity of Hospital at Home and the multidimensional contribution of advanced practice nurses, offering a foundation for future implementation and research.