Spatial Epidemiology of the Ischemic Heart Disease-Asthma Comorbidity: A Global Analysis of Burden Patterns, Risk Drivers, and a Composite Risk Index.

Abstract

Background: Although ischemic heart disease (IHD) and asthma are major contributors to the global disease burden, the geographical distribution patterns of their comorbidity and its macro-level drivers remain unclear. This study aims to analyze the global spatial distribution of IHD-asthma comorbidity and to identify the key risk factors driving this comorbid pattern.

Methods: Based on a secondary analysis of the Global Burden of Disease Study 2021, this study categorized 204 countries and territories worldwide into three spatial patterns-namely "concordant type", "IHD-dominant type", and "asthma-dominant type"-using the quartile method of disability-adjusted life years (DALYs). A three-stage screening approach was employed to identify significant risk factors: random forest modeling combined with Shapley additive explanations was first used to rank and select candidate variables, followed by negative binomial regression analysis to confirm significant associations. Furthermore, population attributable fraction and a composite risk index were constructed to quantify cumulative exposure levels.

Results: Approximately one-quarter of countries worldwide exhibit a "concordant pattern" of disease burden levels, primarily located in Asia, Africa, and Oceania. Thirteen significant risk factors were identified, with deficiency in omega-6 polyunsaturated fatty acids and iron deficiency being common risk factors for both diseases. Overall, 43.083% of IHD DALYs and 28.963% of asthma DALYs were attributable to the combined exposure to their respective risk factors.

Conclusion: The global joint burden of IHD and asthma exhibits substantial spatial heterogeneity, with particularly severe challenges in socioeconomically resource-limited regions of Africa and Asia. Comprehensive strategies integrating nutritional interventions, environmental improvements, and metabolic risk control are crucial for mitigating the global burden of cardiopulmonary comorbidities.