Global health diplomacy as a causal mechanism: a framework linking political determinants of health to population outcomes

Political determinants of health (PDOH) scholarship establishes that power, institutions, interests, and ideologies shape population health. It does not specify how transnational political processes translate into measurable health system outputs. Global health diplomacy (GHD), the process through which state and non-state actors negotiate responses to transnational health problems, is usually treated as descriptive context rather than as a set of causal mechanisms. This paper addresses that specification gap. We conducted a critical integrative review of PDOH, global health governance, and GHD scholarship published between 1990 and 2026, with legal and policy instruments. Of 2148 records identified, 152 entered the synthesis. In the process-tracing sense, a mechanism was defined as a repeated actor-driven process linking a governance decision to an observable health system output. Candidates were retained only if they recurred, could be observed directly, and were distinguishable by the form of power they mobilise. Four outbreak episodes and one Track 2 capacity-building programme were selected against stated criteria. The framework positions GHD as a political determinant operating through four mechanism families: access negotiation, trust and legitimacy, resource mobilisation, and institutional bridging. Each is defined by an observable process, mapped to a form of power, linked to candidate indicators, and paired with an expected outcome and the observation that would count against it. Three conditions bound where the framework applies: armed conflict and fragility, contested multilateral authority, and abrupt financing discontinuity. Each modifies every mechanism. We distinguish vertical trust in institutions from horizontal trust among community members, because both predict health behaviour and conflict degrades both. Every case is mapped to the mechanism it illustrates, showing which evidence supports which claim and where evidence is absent. We then examine the reverse pathway, in which health equity operates as a determinant of political stability, reporting the quantitative estimates alongside the limitations the sources themselves state. Specifying GHD as a set of mechanisms makes diplomacy analysable as a determinant of health rather than as its backdrop. It identifies which pathway a governance shock disrupts and with what expected consequence, so policy responses can be matched to the pathway affected.