Power dynamics and intersectoral collaboration for health in low- and middle-income countries: a realist review.

Intersectoral collaboration (ISC) is a critical strategy in global health for addressing complex challenges requiring multi-sectoral engagement. Although studies examined ISC in low- and middle-income countries (LMICs), gaps remain in understanding how power dynamics between stakeholders influence the effectiveness of ISC in these settings. This realist synthesis examines how, why, for whom, under what context, and to what extent power dynamics shape ISC in LMIC health programmes and policies, offering insights crucial for improving health policy implementation. Five initial programme theories were developed through a scoping review, document analysis, and qualitative study. A systematic search of Medline, Embase, CINAHL, Web of Science, and grey literature (2012-23) yielded 2850 records, with 23 included after screening. This period was chosen to capture contemporary shifts in ISC, following the 2012 UN Political Declaration on NCDs and the WHO's 2013 Health in All Policies (HiAP) framework, which strengthened multi-sectoral governance in LMICs. It also builds on prior reviews, ensuring an up-to-date synthesis of power dynamics in ISC. Data were synthesized using the context-mechanism-outcome framework, generating demi-regularities to refine programme theories (PTs). Findings reveal that power imbalances frequently manifest through hierarchical governance structures, resource disparities, and historical inequities, shaping ISC outcomes. Six refined PTs highlight: (i) inclusive policy development processes mitigate power asymmetries but require intentional facilitation to prevent marginalization of less dominant sectors. (ii) Leadership commitment and shared goal alignment enhance collaboration, yet competing institutional priorities often reinforce power struggles. (iii) Equitable resource allocation acts as both a catalyst for trust and a source of conflict, with donor influence exacerbating dependency dynamics. (iv) Hierarchical communication norms in LMICs undermine transparency, though informal interpersonal networks can circumvent bureaucratic barriers. (v) Ambiguity in roles and mandates amplifies power vacuums, enabling dominant actors to disproportionately influence agendas. Additionally, a sixth PT emerged: (vi) sustained interpersonal relationships counterbalance structural power imbalances, fostering accountability and adaptive problem-solving. These findings demonstrate that power dynamics in ISC within LMICs are mediated by both structural factors (e.g. funding models and institutional hierarchies) and relational mechanisms (e.g. trust and negotiation). Successful collaboration hinges on recognizing and addressing these dual dimensions of power. This synthesis advances the theoretical and practical understanding of ISC, offering policymakers actionable insights to navigate power-related challenges in intersectoral health initiatives.