Horizontal inequity in healthcare access under the universal coverage in Japan; 1986-2007

► We assessed horizontal equity for healthcare access since the late 1980s when Japan faced economic recess and rising copayment. ► Increasing pro-rich inequity was found among non-elderly layer, mainly attributed to increasing needs among the poor. ► To the contrary, relatively high equity was achieved among elderly people who were eligible to reduced copayment rate policy. ► Universal coverage needs continuous redesign of policy to achieve horizontal equity in changing economic environments.