Association of the Dietary Index for Gut Microbiota With Severity, Renal Function, and Sarcopenia in Patients With Chronic Kidney Disease: A Population-Based Cross-Sectional Study

The aim of this research was to clarify the relationship between the Dietary Index for Gut Microbiota (DI-GM) and the severity of chronic kidney disease (CKD), renal function, and the prevalence of sarcopenia in patients with CKD, as well as the role of the Systemic Immune-Inflammation Index (SII) therein. Using data from the National Health and Nutrition Examination Survey (NHANES) 2007-2018, the study included 2169 participants with CKD. DI-GM was calculated on a scale of 0 to 13, with higher scores indicating a healthier gut microbiome. CKD severity was categorized by estimated glomerular filtration rate (eGFR), and sarcopenia was defined using appendicular lean mass adjusted for body mass index. Statistical analyses included weighted regression models, restricted cubic spline, subgroup analysis, and mediation analysis. Higher DI-GM scores were associated with lower CKD severity (odds ratio [OR], 0.85; 95% confidence interval [CI], 0.78-0.94; p = .001), improved renal function (eGFR, β = 1.078, p = .020; serum creatinine, β = -1.548, p = .026; blood urea nitrogen, β = -0.091, p = .026), and reduced sarcopenia prevalence (OR, 0.70; 95% CI, 0.57-0.87; p = .002). SII score partially mediated the association between DI-GM score and sarcopenia in CKD, accounting for 12.11% of the effect (p < .001). No significant associations were found between DI-GM score and all-cause or cardiovascular mortality among the population with CKD. Findings suggest that dietary interventions targeting gut microbiota may have benefits in managing CKD severity, improving renal function, and reducing sarcopenia risk.