Complete Blood Count-Derived Inflammation Indices and Their Association With Cognitive Functions in Patients With Type 2 Diabetes Mellitus

Introduction: The risk of cognitive impairment, including dementia and moderate cognitive impairment (MCI), is higher in patients with diabetes and prediabetes. The need for early diagnosis biomarkers has increased due to the rise in the prevalence of type 2 diabetes mellitus (T2DM) and its related cognitive problems worldwide, as well as the lack of clear biochemical indicators and efficient treatments for dementia or cognitive decline. Chronic low-grade inflammation, reflected by elevated complete blood count-derived inflammatory indices (CBCIIs), has been implicated in both metabolic dysregulation and neurodegeneration. However, their relationship with cognitive impairment in T2DM remains insufficiently explored. The objective of this study was to investigate the association between CBCIIs and cognitive function in patients with T2DM. Methods and materials: This cross-sectional observational study included 116 patients with T2DM recruited from diabetes counseling centers in the Public Institution Health Center of Sarajevo Canton, Bosnia and Herzegovina. Based on the assessed cognitive status, patients with T2DM were divided into two groups: with cognitive impairment (n= 76) and without cognitive impairment (n=40). A validated assessment tool, the Montreal Cognitive Assessment (MoCA), a quick test designed to screen for milder forms of cognitive impairment, was used for cognitive screening. Venous blood samples were analyzed for standard complete blood count parameters, from which 11 CBCIIs were calculated: neutrophil-to-lymphocyte ratio (NLR), derived NLR (dNLR), neutrophil-to-platelet ratio (NPR), neutrophil-to-lymphocyte-to-platelet ratio (NLPR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), aggregate index of systemic inflammation (AISI), systemic inflammation response index (SIRI), lymphocyte-to-monocyte ratio (LMR), and monocyte-to-neutrophil ratio (MNR).. Results: The results of our study showed that NLR, dNLR, NPR, NLPR, PLR, MLR, SII, AISI, and SIRI were significantly higher in the group of T2DM patients with cognitive impairment compared to the group without cognitive impairment. On the other hand, LMR and MNR were significantly lower in the group of T2DM patients with cognitive impairment compared to the group without cognitive impairment (p<0.05). The MoCA score was significantly negatively correlated with NLR, dNLR, NPR, NLPR, and SII, and positively with MNR (p<0.05) Conclusion: Elevated CBCIIs are significantly associated with cognitive impairment in patients with T2DM. These inexpensive and widely available indices may serve as adjunctive markers for early cognitive screening in this population.