Association between systemic inflammation response index and coronary heart disease risk based on NHANES data: A cross-sectional study of trend analysis and epidemiological evidence

Systemic inflammation is increasingly recognized as a critical factor in the development of coronary heart disease (CHD). The systemic inflammation response index (SIRI) integrates the neutrophil, lymphocyte, and monocyte counts to provide a comprehensive inflammatory marker. However, the relationship between the SIRI and CHD risk remains unclear. This study aimed to investigate the association between SIRI and CHD risk in adults using data from the 2012 to 2018 National Health and Nutrition Examination Survey (NHANES) 2012-2018. Restricted cubic spline (RCS) analysis was conducted to explore potential nonlinear relationships, and subgroup analyses were used to evaluate the demographic and clinical modifiers. Logistic regression analysis was performed to assess the association between SIRI and CHD risk after adjusting for demographic, behavioral, and clinical covariates. RCS analysis examined nonlinear trends and subgroup analyses stratified the results by age and sex. Of the 8612 participants initially screened, 1121 were included in the final analysis. Elevated SIRI levels were significantly associated with higher CHD risk (odds ratio [OR] = 1.14, 95% confidence interval [CI]: 1.05-1.25, P < .001). RCS analysis showed a linear relationship between the SIRI and CHD risk (P for nonlinearity = .056). Subgroup analysis demonstrated stronger associations in males (OR = 1.21, 95% CI: 1.10-1.34) and individuals aged ≥55 years (OR = 1.18, 95% CI: 1.08-1.29), whereas no significant associations were found in female or younger populations. This study underscores the utility of the SIRI as a potential biomarker for CHD risk. The linear association between the SIRI and CHD risk emphasizes the importance of systemic inflammation, particularly in males and older adults. Further studies should investigate targeted anti-inflammatory interventions to potentially reduce CHD risk. However, due to the cross-sectional design of this study, it is important to note that no temporal or causal relationship can be inferred between SIRI levels and CHD risk intention-to-treat.