Trends in amenable deaths based on township income quartiles in Taiwan, 1971-2008: Did universal health insurance close the gap?

Abstract

Background: Few studies have explored the association between income and mortality in Asian populations. We documented the temporal trend in amenable mortality in Taiwan based on township income quartiles between 1971 and 2008, and analyzed whether universal access to care implemented in 1995 eliminated any income-based mortality disparities. Methods: Data were obtained from Taiwan's National Death Certification Registry and the National Statistics Bureau. Age-standardized mortality rates (ASMRs) were calculated, disaggregated by gender and township income quartiles. Segmented regression analyses were performed and slope indices of inequality were calculated to assess the impact of universal access on amenable mortality. Results: ASMRs for deaths amenable to medical care fell for all income quartiles, but by greater magnitudes for the richer townships from 1971 to 2008. For virtually all deaths amenable to medical care, the richer townships had the lowest ASMRs by 2006-08. Universal access to care may have slowed the growth of ischemic heart disease for men living in the poorest townships, but its impact on aggregate amenable mortality was limited. Conclusions: An income gradient persisted throughout the study period. Guaranteed access to medical care may have helped reduce but did not eliminate the income gradient in mortality disparities.