Blood glucose mediation of the association between SIRI and mortality in T2DM complicated with ischemic stroke

The co-occurrence of type 2 diabetes mellitus (T2DM) and ischemic stroke presents a significant global public health challenge and is associated with adverse clinical outcomes. The relationship between the Systemic Inflammatory Response Index (SIRI) and mortality in patients with T2DM complicated with ischemic stroke remains poorly understood. This study aimed to investigate the relationship between SIRI and mortality in this population, further exploring the potential mediating role of blood glucose levels. We analyzed data from the MIMIC-IV database, selecting patients with T2DM complicated with ischemic stroke. Using multivariable Cox regression, restricted cubic splines(RCS), and Kaplan-Meier analysis, we assessed the association between SIRI and all-cause mortality. We also employed mediation analysis to examine the role of blood glucose in this relationship. The study enrolled a total of 1235 patients. Elevated SIRI levels were significantly associated with increased 28-day (HR: 1.09, 95%CI:1.07-1.12, P < 0.01) and 1-year (HR: 1.08, 95%CI:1.06-1.10, P < 0.01) mortality in this patient group. A nonlinear relationship between SIRI and mortality in this patient population was evident from the RCS analysis(P < 0.01). Subgroup analysis revealed that the effect size and direction remained consistent across different subgroups, indicating the stability of the results.Mediation analysis estimated that blood glucose accounted for approximately 13.72% of the total association between SIRI and 28-day mortality (P < 0.01), but not for 1-year mortality (P = 0.17). These findings demonstrate that elevated SIRI is associated with increased short- and long-term mortality among T2DM complicated with ischemic stroke. Blood glucose plays a mediating role in the relationship between SIRI and 28-day mortality.