Spatial Accessibility and Equity of Institutional Aged Care in an Ageing Chinese City: A GIS-Based Study of Changsha

Institutional aged care is essential in ageing societies, but its spatial accessibility and equity remain insufficiently understood in rapidly growing Chinese cities. Using Changsha, this study combined an adapted Three-Step Floating Catchment Area (3SFCA) model with Gini and Theil diagnostics to estimate accessibility in 2020 and under a conditional 2030 scenario with facility supply fixed at its 2020 level. The model incorporated Gaussian distance decay, a 40 km baseline catchment, and tertiary-hospital proximity as an exploratory proxy for medical-support attractiveness. Accessibility was estimated on 500 m × 500 m demand grids; equity was assessed across subdistricts/townships. Under the 0.04 beds-per-person planning reference, 19% of populated grids met the benchmark in 2020 and 7% did so in the 2030 scenario. Non-central jurisdictions generally had higher modelled accessibility than central districts despite denser facility networks in the urban core, reflecting bed capacity, demand concentration, impedance, and competition. The Gini coefficient changed from 0.260 to 0.259 and the total Theil index from 0.066 to 0.065; the within-district component accounted for 82.134% and 84.056% of total Theil inequality, respectively. Alternative catchments, travel modes, and exclusion of the hospital-proximity term materially changed coverage and inequality. The findings identify neighbourhood-scale shortages and support differentiated planning, while the 2030 results should be read as a fixed-supply stress test rather than a forecast.