Atherosclerotic coronary artery disease (CAD) is the leading cause of mortality worldwide. 1 In this context, the burden of CAD shows considerable regional heterogeneity at the national level. For example, age-standardized mortality rates varied between 106 and 178 deaths per 100 000 at the level of German federal states in 2019. 2 The regional heterogeneity of cardiovascular mortality suggests that the residential environment should be considered as an important determinant for successful secondary prevention. Environmental features that were frequently drawn upon to explain regional inequalities of cardiovascular outcomes are spatial socioeconomic deprivation (SSD) and rurality. 3 Rurality may impact cardiovascular health due to impaired access to healthcare services. Socioeconomically deprived neighbourhoods, on the other hand, exhibit restricted opportunities to eat healthy, exercise regularly, utilize health care, and avoid environmental hazards such as air pollution. 3

Repeated activation of compensatory mechanisms to counter these harmful exposures may lead to dysregulation of the immune and metabolic system, chronic inflammation, and oxidative stress. 4 An emerging body of research suggests that chronic systemic oxidative stress and inflammation are accompanied by high levels of dysfunctional highdensity lipoprotein (HDL), and that dysfunctional HDL is associated with worse outcomes among cardiovascular patients. 5, 6 Hence, we investigated the association of SSD and rurality with dysfunctional HDL to explore spatial inequalities of oxidative stress and inflammation among patients with CAD. In this study, we used a cell-free