The Dietary Inflammatory Index is Associated with Reduced Kidney Function in Atherosclerotic Cardiovascular Disease Patients

Abstract Background Dietary patterns are strongly correlated with chronic inflammation. Inflammatory processes play a crucial role in maintaining renal homeostasis and function. The dietary inflammatory potential can be assessed through the Dietary Inflammatory Index (DII), which has shown a positive association with a higher likelihood of chronic kidney disease (CKD) in healthy individuals. However, the applicability of DII in assessing atherosclerotic cardiovascular disease (ASCVD) patients has not been evaluated. Methods This cross-sectional study enrolled 3,599 adult participants with ASCVD taken from the National Health and Nutrition Examination Survey (NHANES) conducted between 1999 and 2018. Systematic collection of baseline data was performed for all study participants. Patients were categorized into four groups according to the baseline DII. The association of kidney function with the DII score was assessed using linear regression analysis. Multivariable logistic regression was conducted to investigate the correlation between the DII score and the likelihood of CKD. Furthermore, a restricted cubic spline (RCS) analysis was employed to explore potential non-linear correlations between the DII score and CKD. Results In regression models adjusted for a range of possible confounders, the DII score demonstrated a positive correlation with serum creatinine (p < 0.001) and an inverse correlation with the estimated glomerular filtration rate calculated using the MDRD equation (p < 0.001). Compared to individuals without CKD, those with CKD had significantly elevated DII scores (p < 0.001). Multivariable logistic regression analysis revealed a significant association between high DII scores and CKD; after classifying DII into quartiles and fully adjusting, individuals in the highest quartile (quartile 4) showed a positive and significant association with an increased risk of chronic kidney disease compared to those in the lowest quartile (quartile 1) (95% CI: 1.045–1.613, P = 0.019). Using restricted cubic spline analysis, a linear relationship was uncovered between the DII score and the risk of developing kidney disease in all study participants. Conclusion The study utilized the Dietary Inflammatory Index to assess dietary inflammatory potential in adults diagnosed with ASCVD. The findings revealed that a high DII score was associated with decreased kidney function in ASCVD patients and was an independent risk factor for the development of CKD. Our findings underscore the importance of maintaining a diet low in the inflammatory potential to reduce the risk of CKD in this population.