Regional Disparities in the Prevalence of Hypertension and Diabetes Mellitus According to the Degree of Urbanization (DegUrba): A Cross-Sectional Study Using the 2020 Korean Community Health Survey

Background Despite South Korea’s achievement of Universal Health Coverage (UHC), regional health inequities persist as a significant public health challenge. Traditional urban-rural classifications often fail to capture the nuanced spatial dynamics of modern settlement patterns. This study aimed to evaluate the prevalence of hypertension (HTN) and diabetes mellitus (DM) across the urbanization gradient—Cities, Towns, and Rural areas—using the UN-recommended Degree of Urbanization (DegUrba) classification. Methods We conducted a cross-sectional analysis of 154,829 adults residing in Gyeonggi-do, utilizing the 2020 Korean Community Health Survey (KCHS) data. Regions were categorized into Cities (Urban Centers), Towns and Semi-dense Areas (Urbanized), and Rural Areas based on 1km² population grid cells. Prevalence and subgroup interactions were analyzed using complex sampling weights to ensure regional representativeness. Results A distinct geographic disparity was observed: rural areas exhibited the highest prevalence of HTN (36.31%) and DM (14.65%), significantly exceeding those in Cities (HTN: 23.04%, DM: 10.01%) and Urbanized Towns (HTN: 20.24%, DM: 9.31%). Urbanized Towns showed the lowest prevalence for both conditions. Subgroup analysis demonstrated that the prevalence gap between rural areas and urbanized towns was most pronounced among elderly females and individuals with lower educational attainment. Conclusion Regional disparities in chronic disease prevalence remain pronounced despite the UHC system, with rurality serving as a strong independent determinant. These findings suggest that healthcare equity cannot be achieved by financial coverage alone. There is an urgent need for density-aware, targeted community-based interventions focusing on socioeconomically vulnerable rural populations to mitigate the cardiovascular burden.