Elevated atherogenic index of plasma is associated with increased cardiorenal syndrome prevalence: a cross-sectional study

Cardiorenal syndrome (CRS) is a complex clinical condition characterized by the simultaneous dysfunction of the heart and kidneys. The atherogenic index of plasma (AIP), calculated as the logarithm of the ratio of triglycerides (TG) to high-density lipoprotein cholesterol (HDL-C), has emerged as a potential biomarker for cardiovascular risk. This study investigates the association between AIP and CRS, aiming to explore the potential linkage between AIP and CRS. Data were sourced from the National Health and Nutrition Examination Survey spanning 2005–2018, involving 35,365 participants after applying exclusion criteria. The primary exposure variable was AIP, categorized into quartiles, while the primary outcome variable was CRS, defined by the coexistence of cardiovascular disease (CVD) and chronic kidney disease (CKD). Statistical analyses, considering sample weights, included ANOVA, Chi-square tests, logistic regression models, and restricted cubic spline (RCS) analysis to examine nonlinear relationships. The weighted logistic regression analysis showed a positive correlation between AIP and CRS across all models. In the fully adjusted model, the highest AIP quartile had a significantly increased odds ratio (OR) for CRS (Q4: OR = 1.62; 95% CI: 1.21–2.15). RCS analysis confirmed a positive correlation between AIP and CRS, with TG positively and HDL-C negatively correlated with CRS. Subgroup analysis indicated a significant interaction with hypertension, showing a stronger association in non-hypertensive individuals. Higher AIP levels are associated with an increased prevalence of CRS, with a notable hypertension-specific interaction indicating a higher effect in individuals without hypertension.