Comparison of Dietary Inflammatory Index Scores with Inflammatory and Anthropometric Metrics in Individuals Receiving Maintenance Hemodialysis

Abstract

ObjectivesThe modified dietary inflammatory index (DII) is a scoring tool that reflects inflammatory influence of diet components and has been studied as a predictor of inflammatory markers. This study explored correlations between modified DII scores, C-reactive protein (CRP), and conicity index (Ci) in patients receiving maintenance hemodialysis (MHD). MethodsThis study was a secondary analysis of 142 participants in the Rutgers Nutrition and Kidney Disease database. Food intake data were collected using the NHANES multi-pass method and were reflective of a dialysis treatment day. The modified DII scores were divided into tertiles; tertile 1 had the least inflammatory (negative) and tertile 3 had the most inflammatory (positive) scores. Correlations between DII scores, CRP, and Ci were measured using Spearman’s and Pearson’s Coefficients. Between tertile differences were compared using Kruskal-Wallis and ANOVA. ResultsThe median age was 55.3 years and 59.2% were male. The majority were African American (83.8%) and non-Hispanic (77.5%). The range of modified DII scores was –9.7 to 536.0, and the median score was 203.2, indicating a pro-inflammatory diet. The median scores for tertille 3 (338.1) were significantly higher than tertiles 1 or 2 (114.6 and 201.5, p-value < 0.001). Tertile 3 consumed more omega-3 fats, fiber, calories, total fat, and saturated fat. The median CRP and Ci were 5.6 mg/L and 1.33 ± 0.1, and did not differ significantly by tertile. A non-significant, small, positive correlation was observed between DII scores and CRP (r = 0.161, p = 0.071), but not for Ci (r = 0.046, p = 0.586). ConclusionsThis sample consumed a mostly pro-inflammatory diet. Food selections may be the result of consuming convenience foods on dialysis days, which are generally pro-inflammatory. Regardless, in our sample the pro-inflammatory dietary intakes did not correlate with markers of inflammation, likely due to homogeneity across the tertiles. While exploratory, this tool may assist clinicians in assessing patients on MHD who may benefit from individualized nutrition therapy to reduce their risks for chronic inflammation. Funding SourcesResearch reported in this publication was supported by the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (awards 1R15DK090593-01A1,6R15DK090593-02, and 3R15DK090593-02S1).