Predictive Value of Routine Peripheral Blood Biomarkers in Alzheimer's Disease

Abstract

Background: Biomarker screening is of major significance for the early diagnosis and prevention of Alzheimer's disease (AD). Routine peripheral blood parameters are easy to collect and detect, making them ideal potential biomarkers. Thus, we aimed to evaluate the parameters from routine blood as potential biomarkers for AD.

Methods: We enrolled 56 AD patients, 57 mild cognitive impairment (MCI) patients, and 59 healthy elderly controls. Receiver operating characteristic (ROC) curves were used to assess the diagnostic values of routine blood biomarkers in patients with cognitive impairment.

Results: There were significant differences in eight parameters between the groups. Logistic regression revealed that the neutrophil% (odds ratio (OR) 1.34, 95% confidence interval [CI] 1.03-1.75, p = 0.031) and neutrophil-to-lymphocyte ratio (NLR; OR 6.27, 95% CI 3.98-9.82, p = 0.003) differentiated AD patients and controls (areas under the curve [AUCs], 0.728 and 0.721) and that the NLR (OR 1.93, 95% CI 1.07-3.47, p = 0.028) and mean platelet volume (OR 1.67, 95% CI 1.04-2.70, p = 0.036) differentiated MCI patients and controls (AUCs, 0.60 and 0.638). There were no effective diagnostic biomarkers to distinguish AD from MCI.

Conclusion: Some routine blood biomarkers may correlate with cognitive impairment. Analysis of these biomarkers, such as the NLR, may be useful for the identification of patients with cognitive impairment.

Keywords: Alzheimer disease; aging; biomarkers; blood routine; mild cognitive impairment.

FIGURE 1

Boxplots for the eight parameters (A–H) with significant differences in concentrations between diagnostic groups. AD, Alzheimer’s disease; MCI, mild cognitive impairment; CTRs, controls; PDW, platelet distribution width; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet-to-lymphocyte ratio.

FIGURE 2

(A) AD patients and CTRs are differentiated by the NLR with a predictive power (AUC) of 0.721 (violet line) and by the neutrophil% with a predictive power (AUC) of 0.728 (red line). (B) MCI patients and CTRs are differentiated by the NLR with a predictive power (AUC) of 0.601 (green line) and by the MPV with a predictive power (AUC) of 0.690 (blue line).