Systemic immuno-inflammation index in Alzheimer’s disease

Abstract Objectives The aim of our study was to evaluate the diagnostic and prognostic significance of systemic immune inflammation index (SII) and other hematological parameters in Alzheimer’s disease (AD), the most common cause of dementia in the world. Methods This retrospective study analyzed 340 patients with Alzheimer’s disease and 340 healthy controls. Demographic, cognitive, SII, neutrophil-to-lymphocyte ratio (NLR), monocyte-to-neutrophil ratio (MNR), platelet-to-monocyte ratio (PMR), and biochemical parameters were compared between the groups. Results Neutrophil, monocyte, and platelet counts, as well as NLR and SII values, were significantly higher in the AD group compared to the control group. However, lymphocyte, hemoglobin, high-density lipoprotein cholesterol, and PMR values were lower in the patient group (all p<0.001). Mini Mental State Examination scores were found to be negatively correlated with NLR, SII, and monocyte counts, and positively correlated with lymphocyte counts and PMR. In the multivariate model, PMR and MNR were found to be independent predictors of AD, while SII and NLR were not. A positive correlation was found between disease severity and SII, and a negative correlation was found between MNR. Conclusions SII and NLR are elevated in Alzheimer’s disease (AD) and correlate with cognitive function loss. MNR and PMR are attracting attention as independent predictors of AD, providing new data compared to previous studies. These readily and inexpensively obtained parameters may serve as potentially practical tools for early or preclinical diagnosis, risk stratification, and monitoring of Alzheimer’s disease.