Higher Dietary Inflammatory Index and Systemic Immune-Inflammation Index Score are Associated With Higher Risk of Chronic Kidney Disease: Analysis of the National Health and Nutrition Examination Survey From 1999 to 2018.

Objective: Chronic kidney disease (CKD) is characterized by a gradual decline in kidney function over time. The role of dietary inflammatory index (DII) and systemic immune-inflammation index (SII) in individuals with CKD remains uncertain. We aimed to explore the potential correlation between DII and SII with the prevalence of CKD in adult Americans.

Methods: This cross-sectional study used data from the National Health and Nutrition Examination Study between 1999 and 2018. The DII was calculated based on the 24-hour dietary history interview, while the SII was calculated as the product of platelet count multiplied by neutrophil count and divided by lymphocyte count. CKD was diagnosed based on impaired glomerular filtration rate (<60 mL/min per 1.73 m) or urinary albumin-creatinine ratio ≥30 mg/g. Multivariable logistic regression analyses and subgroup analyses were performed to examine the association between DII/SII and CKD.

Results: In total, this study included 40,388 participants, of whom 7443 (18.4%) had CKD. The prevalence of CKD changed from 14.84% (95% confidence interval (CI): 13.20-16.48%) in 1999-2000 to 12.76% (95% CI: 11.10-14.43%) in 2017-2018. According to adjusted multivariate logistic regression models, individuals with higher DII scores had a higher likelihood of having CKD (odds ratio = 1.24; 95% CI: 1.12-1.37). Similarly, higher SII scores were associated with a higher risk of CKD (odds ratio = 1.37; 95% CI: 1.25-1.50). Subgroup analyses further demonstrated relatively stronger associations between DII/SII and CKD among individuals with other factors such as sex, age, body mass index, smoking status, drinking status, hypertension, and diabetes.

Conclusions: The DII and SII scores were significantly positively associated with higher risks of CKD. Anti-inflammatory diet might have the potential to prevent CKD. The SII may serve as a cost-effective and straightforward approach for detecting CKD. Further prospective longitudinal studies are needed to verify the causality.