Defining and classifying public health systems: a critical interpretive synthesis.

Background: The introduction of the determinants of health has caused a shift towards understanding health from a holistic perspective as well as increased recognition of public health's contributions to the health of the population. Several frameworks exist to conceptualise healthcare systems, highlighting the stark contrast of frameworks unique to public health systems. The objectives of this study were to define public health systems and assess differences between healthcare systems and public health systems within established health systems frameworks.

Methods: A critical interpretive synthesis was conducted. Databases searched included EBSCOhost, OVID, Scholars Portal, Web of Science, Cochrane Library and Health Systems Evidence. Data extraction, coding and analysis followed a best-fit framework analysis method. Initial codes were based on a current leading health systems and policy classification scheme - health systems arrangements (governance, financial and delivery arrangements).

Results: A total of 5933 unique documents were identified and 67 were included in the analysis. Definitions of public health and public health systems varied significantly as did their roles and functions across jurisdictions. Public health systems arrangements generally followed those of health systems, with the addition of partnerships (community and inter-sectoral) and communication playing a larger role in public health. A public health systems framework and conceptualisation of how public health currently fits within health systems are presented.

Conclusions: Public health systems are unique and vital entities within health systems. In addition to examining how public health and public health systems have been defined within the literature, this review suggests that establishing the scope of public health is crucial to understanding its role within the larger health system and adds to the discourse around the relationship between public health, healthcare and population health. More broadly, this study addresses an important gap in understanding public health systems and provides conceptual and practical contributions as well as areas for future research.