Association of Elevated Systemic Inflammatory Response Index with Diabetic Kidney Disease in Type 2 Diabetes
Background Diabetic kidney disease (DKD) is a major microvascular complication of type 2 diabetes mellitus (T2DM). Chronic low-grade inflammation has been implicated in the development and progression of DKD. The systemic inflammatory response index (SIRI), a novel composite inflammatory biomarker, has demonstrated prognostic value in various inflammatory and metabolic disorders. However, evidence regarding the association between SIRI and DKD remains limited. Methods This retrospective cross-sectional study included 2421 hospitalized patients with T2DM. DKD was defined according to established clinical criteria. Multivariable logistic regression models were used to evaluate the association between SIRI and DKD after adjustment for demographic and clinical covariates. Restricted cubic spline (RCS), receiver operating characteristic (ROC), subgroup, sensitivity, and mediation analyses were additionally performed. Results Among the 2,421 participants, 892 (36.8%) were diagnosed with DKD. Higher SIRI levels were significantly associated with increased odds of DKD in multivariable logistic regression analyses. Participants in the highest SIRI category had substantially greater odds of DKD compared with those in the lowest category. RCS analysis demonstrated a nonlinear positive association between SIRI and DKD risk. ROC analysis showed that the combination of age, sex, and SIRI had better discrimination ability for DKD than SIRI alone. Subgroup analyses demonstrated generally consistent associations across predefined subgroups, although significant interactions were observed for age and HbA1c status. Mediation analysis indicated that eGFR partially mediated the association between SIRI and DKD, accounting for approximately 46% of the total effect. Conclusion Elevated SIRI was independently associated with increased odds of DKD in patients with T2DM. The association appeared nonlinear and was partially mediated through renal function impairment. SIRI may serve as a convenient inflammatory biomarker for identifying patients at higher risk of DKD.