Potential utility of a regional oral health policy indicator system: an analysis of oral health screening indicators in Gangwon State using NHIS administrative data

Objectives: This study examined the potential utility of regional oral health policy indicators derived from National Health Insurance Service (NHIS) administrative data in Gangwon State during 2018-2024: infant and adult oral screening rates, oral-screening self-sufficiency, and dental-provider participation.Whether the indicators informed subsequent annual program plans or were associated with program outcomes was beyond the scope of this study.Methods: We combined a repeated cross-sectional ecological analysis of NHIS administrative data with a review of municipal oral health program documents.Infant and adult oral screening rates and oralscreening self-sufficiency were calculated at the national, provincial, and municipal levels.The dentalprovider participation rate was calculated for Gangwon State and its municipalities at available survey points.Crude rates described 2018-2024 trends; age-standardized adult screening rates were used for 2024 regional comparisons.Using aggregated numerators and denominators, municipal heterogeneity was assessed with grouped binomial models for oral screening rates and Pearson chi-square tests for self-sufficiency and provider participation.The exploratory four-quadrant typology used two external benchmarks: the 2022 national mean provider participation rate (60.5%) and the 2024 national oralscreening self-sufficiency rate (76.5%).Municipal program plans and reports for 2024 were reviewed by typology.Results: In 2024, Gangwon State had a higher infant oral screening rate than the national rate (51.4% vs. 48.4%)but lower adult oral screening (24.7% vs. 27.7%,age-standardized) and self-sufficiency rates (72.8% vs. 76.5%).Across municipalities, adult oral screening rates ranged from 8.4% to 41.8% and self-sufficiency rates from 27.5% to 89.2%.Municipal heterogeneity was significant for all four indicators (P<0.001).Two municipalities were type a (high participation-low self-sufficiency), three type b (high participation-high self-sufficiency), twelve type c (low participation-low self-sufficiency), and one type d (low participation-high self-sufficiency).Few municipal program strategies were explicitly linked to the indicator typology.Conclusions: NHIS administrative indicators could be compiled repeatedly and used to identify meaningful municipal variation, supporting their potential utility as regional oral health policy indicators.However, their linkage to municipal program strategies remained limited.Integrating these indicators into a unified policy indicator system may help formulate type-specific policy questions and tailored regional strategies.