Systemic inflammation is associated with increased risk of death in population with atherosclerotic cardiovascular disease and chronic kidney disease-a Danish national register study.

Aims: Systemic inflammation (SI), indicated by elevated C-reactive protein (CRP) levels, is known to increase the risk of major adverse cardiovascular events (MACE) and mortality. This study aims to investigate the association between SI and mortality in the Danish population diagnosed with atherosclerotic cardiovascular disease ASCVD and chronic kidney disease CKD. Methods: We identified 19,159 individuals with incident ASCVD and CKD between 2012 and 2022 in Danish national health registers. SI was defined by at least two CRP measurements between 2 mg/L and 20 mg/L within a six-month period. Cox proportional hazards models were employed to assess the relationship between SI and mortality, adjusting for relevant confounders. Results: Among the cohort, 68% were observed with SI. SI were associated with significantly higher risk of mortality, with a hazard ratio (HR) of 2.06 (95% CI: 1.92-2.21) for death and 1.66 (95% CI: 1.57-1.77) for 'MACE or death'. The results were consistent in all subgroup analyses and sensitivity analyses, including in men and women separately, and using different definitions of SI. Conclusion: This study demonstrates that SI is prevalent among patients with ASCVD and CKD being strongly associated with higher risk of mortality and MACE. These findings suggest that SI could serve as a valuable marker to identify patients with ASCVD and CKD who are at particularly high risk and may benefit from targeted preventive interventions.