Income based disparities in ischemic heart disease mortality a global analysis of age standardized death rates (1990 to 2021)

Abstract Background Ischemic Heart Disease (IHD) remains a major global health burden, with socioeconomic disparities affecting mortality trends globally. Purpose This study analyzes global trends in age-standardized IHD mortality from 1990 to 2021 across Socio-Demographic Index (SDI) groups to assess income-based disparities. Methods GBD data was analysed to assess the mortality rates for IHD from 1990 to 2021 across five SDI groups. Annual Percent Change (APC) and Average Annual Percent Change (AAPC) were calculated to determine mortality rate trends over time, with p-values determining the statistical significance. Results Global age-standardized IHD mortality declined by 30%, from 158.9 per 100,000 in 1990 to 111.5 in 2021, highlighting a significant three-decade reduction. The AAPC was -1.30% (CI: -1.34 to -1.26) with a highly significant p-value, indicating a clear decreasing trend. In low SDI regions, IHD mortality declined by 9.4% from 1990 to 2021. From 1990–2013, the decline was slow (APC = -0.20%, 95% CI: -0.30 to -0.09), but from 2014–2021, it accelerated (APC = -1.13%, 95% CI: -1.57 to -0.68). The overall trend shows no significant change (AAPC = 0.01, CI: -0.10 to 0.11). In low-middle SDI regions, mortality decreased by 13%. From 2014–2021, a moderate decline was observed (APC = -0.64%, 95% CI: -1.00 to -0.26). However, overall, there was a slight but significant increase (AAPC = 0.16, CI: 0.09 to 0.23). In middle SDI regions, mortality declined by 11%. From 2011–2021, the trend showed a steady decrease (APC = -0.78%, 95% CI: -0.99 to -0.56). Overall, a small but significant decline was observed (AAPC = -0.12, CI: -0.19 to -0.04). In high-middle SDI regions, mortality dropped by 26%. From 1990–2006, the decline was slow (APC = -0.33%, 95% CI: -0.58 to -0.07), but from 2007–2021, the decline accelerated sharply (APC = -2.41%, 95% CI: -2.77 to -2.05). The overall trend shows a significant decrease (AAPC = -1.56, CI: -1.77 to -1.36). In high SDI regions, mortality fell by 49%. From 1990–2010, a steep decline was observed (APC = -3.62%, 95% CI: -3.72 to -3.50), which slowed slightly from 2011–2021 but remained significant (APC = -2.39%, 95% CI: -2.66 to -2.11). These regions showed the most substantial overall decline (AAPC = -3.43, CI: -3.53 to -3.32, p 0.0001). Conclusions IHD mortality has declined globally, with high-income regions achieving the earliest and steepest reductions, though progress has slowed. Low- and middle-income regions saw slower improvements initially but experienced a faster decline in the 2010s. High-middle SDI regions showed the most significant improvement after 2007, driven by economic growth and healthcare advancements. Despite progress, sustained efforts are needed for equitable cardiovascular care.