Multi factor assessment of spatial accessibility for rural health equity in Diqing China.

Timely access to essential primary healthcare services is critical for achieving health equity, particularly in geographically constrained mountainous regions where terrain imposes significant barriers to mobility. However, existing national planning standards in China rely on uniform service radii or walking-time thresholds, often failing to reflect the true accessibility conditions in complex highland environments. To address this gap, this study develops a Multi-Factor Integrated Mountain Walkability Model (MIMWM) that incorporates high-resolution Digital Elevation Models, slope-adjusted walking speeds, land-use resistance coefficients, and physiological walking capacity decline at altitude. Embedded within the Two-Step Floating Catchment Area framework, the model is applied to Diqing Tibetan Autonomous Prefecture in Yunnan Province, a high-altitude region characterized by rugged terrain and sparse healthcare infrastructure. Results demonstrate that traditional Euclidean and network-based methods substantially overestimate accessibility, particularly within the 15-60 min walking thresholds. The MIMWM reveals a critical threshold effect at approximately 30 min, beyond which accessibility improvements diminish. Moreover, most residents in the study area fall below the baseline criteria for access set by national healthcare standards, highlighting the inadequacy of uniform service thresholds in mountainous settings. This study underscores the dominant influence of terrain and walking capacity constraints and advocates for location-specific accessibility metrics and near-distance infrastructure investment to improve rural health equity. The model provides a replicable approach for integrating terrain sensitivity into healthcare accessibility planning in other topographically complex regions.