Decomposed Trends of Iranian Private Health Expenditures: Should Inequality be Appreciated?

Inequalities in health and health care have drawn considerable attention in social determinants of health literature. This study aims to calculate the inequality of out-of-pocket health payments (OPHP) for Iranian households during the period 1984 to 2019 and provide decomposed inequality for households with different socioeconomic status. This longitudinal study utilized the Iranian Statistics Centre data on Iranian household income and expenditures survey. The analysis includes a total of 995,300 households during a 36-year period from 1984 to 2019. The Theil index and the mean logarithmic deviation were used to decompose inequality into within-group and between-group for OPHP among Iranian households. The findings indicate that the mean of the Theil index for the households covered by insurance is 1.44 (SD ± 0.34), while the index was 1.35 (SD ± 0.31) for households without insurance coverage. The mean of the Theil index for rural and urban households was 1.29 (SD ± 0.29) and 1.43 (SD ± 0.33), respectively. Regardless of the fluctuations, the trends of between- group and within group inequalities in OPHP were almost similar until 2011, but they followed a different path since then. Households living in cities, households with insurance coverage, and households in high income levels have experienced more inequality in OPHP than other households. This study provides a novel interpretation of inequality in health care expenditures and provides a long-term time series data to assess the effectiveness of implemented policies in health care system.