The benefits of an integrated social medical insurance for health services utilization in rural China: evidence from the China health and retirement longitudinal study

BACKGROUND: Improving health equity is a fundamental goal for establishing social health insurance. This article evaluated the benefits of the Integration of Social Medical Insurance (ISMI) policy for health services utilization in rural China. METHODS: Using the China Health and Retirement Longitudinal study (2011‒2018), we estimated the changes in rates and equity in health services utilization by a generalized linear mixed model, concentration curves, concentration indices, and a horizontal inequity index before and after the introduction of the ISMI policy. RESULTS: For the changes in rates, the generalized linear mixed model showed that the rate of inpatient health services utilization (IHSU) nearly doubled after the introduction of the ISMI policy (8.78 % vs. 16.58 %), while the rate of outpatient health services utilization (OHSU) decreased (20.25 % vs. 16.35 %) after the implementation of the policy. For the changes in inequity, the concentration index of OHSU decreased significantly from − 0.0636 (95 % CL: −0.0846, − 0.0430) before the policy to − 0.0457 (95 % CL: −0.0684, − 0.0229) after it. In addition, the horizontal inequity index decreased from − 0.0284 before the implementation of the policy to − 0.0171 after it, indicating that the inequity of OHSU was further reduced. The concentration index of IHSU increased significantly from − 0.0532 (95 % CL: −0.0868, − 0.0196) before the policy was implemented to − 0.1105 (95 % CL: −0.1333, − 0.0876) afterwards; the horizontal inequity index of IHSU increased from − 0.0066 before policy implementation to − 0.0595 afterwards, indicating that more low-income participants utilized inpatient services after the policy came into effect. CONCLUSIONS: The ISMI policy had a positive effect on improving the rate of IHSU but not on the rate of OHSU. This is in line with this policy’s original intention of focusing on inpatient service rather than outpatients to achieve its principal goal of preventing catastrophic health expenditure. The ISMI policy had a positive effect on reducing the inequity in OHSU but a negative effect on the decrease in inequity in IHSU. Further research is needed to verify this change. This research on the effects of integration policy implementation may be useful to policy makers and has important policy implications for other developing countries facing similar challenges on the road to universal health coverage. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12939-021-01457-8.