Measuring and decomposing socioeconomic-related inequality in the use of oral health services among Chinese adults.

Abstract

This study aimed to measure socioeconomic-related inequality and horizontal inequity in the use of oral health services and decompose this inequality among adults of different age groups in China. In total, 10973 adults (3669 aged 35-44years, 3767 aged 55-64years and 3537 aged 65-74years) who participated in the 4th National Oral Health Survey (2015-2016) in China were included. Concentration curves and the Erreygers-corrected concentration index (EI) were employed to measure socioeconomic-related inequality in the use of oral health services. Then, inequity in this utilization was measured by the horizontal inequity index (HI). Furthermore, decomposition analyses were conducted for the three groups to explain the contributions of income level, need factors (ie self-assessed oral health and evaluated oral health status), other factors (ie sex, residential location, educational attainment level and type of basic insurance) and a residual term to overall inequality in oral health service utilization. The significant positive EI and HI values indicated that pro-rich inequality and inequity in oral health service utilization exist among Chinese adults. Income and type of basic medical insurance contributed the most to socioeconomic-related inequality in the use of oral health services among adults aged 55-64 and 65-74years. However, the main driving factors of socioeconomic inequality among adults aged 35-44years in dental care use included income, educational achievement, type of basic medical insurance and residential location. The need variables accounted for a very small proportion of overall socioeconomic-related inequality in oral health service use in all three groups. Oral healthcare service utilization was disproportionately concentrated among better-off Chinese adults. The primary determinants of inequality in dental care use in different age groups provide information for policymakers to create more targeted policies to achieve equity in the oral healthcare system in China.