From growth to well-being: pathways and social security effects of coordinating medical resources and population in the Yangtze River Delta region

The effective allocation of Medical and Healthcare (M&H) resources is crucial to the capacity of the social security system in safeguarding and enhancing residents' health and well-being. To examine the coordination between this specific social security subsystem and the population it serves within the context of urbanization, this study takes the Yangtze River Delta (YRD) region from 2000 to 2022 as a case study. It focuses on the dynamic relationship between the permanent resident population (PRP) and the supply level of M&H resources. An allometric growth model is constructed to analyze the spatiotemporal evolution of their allometric relationship, and a Boosted Regression Tree (BRT) model is employed to identify the underlying influencing mechanisms. The main findings are as follows: (1) Both the PRP and M&H resources in the YRD region showed a consistent upward trend during the study period, with a spatial pattern generally declining from east to west. (2) In terms of vertical allometric growth, the scale index exhibited an increasing trend, and the allometric relationship evolved through three distinct stages: "PRP expansion," "basic coordination between PRP and M&H resources," and "M&H resources expansion." Regarding horizontal allometric growth, from 2000 to 2010, cities with positive and negative allometric growth were nearly equal in number, displaying a spatial pattern of positive growth in the south and negative growth in the north. In contrast, from 2011 to 2022, most cities experienced positive allometric growth. (3) Factors such as industrial structure, medical consumption, population attraction, economic development, population concentration, and aging were identified as key drivers influencing allometric growth. While the marginal effects of these factors varied, their combined influence facilitated shifts in the allometric relationship. (4) The role of economic mechanisms in driving allometric growth weakened under market forces, whereas social mechanisms played an increasingly significant role. Initially, social factors accelerated growth within a market-regulated context; later, under government macroeconomic regulation, their impact further intensified. Consequently, regional integration in the YRD region progressively extended into the domain of public services, with this process gaining substantial momentum.