C-Reactive Protein/Albumin and Neutrophil/Albumin Ratios as Novel Inflammatory Markers in Patients with Schizophrenia

Abstract

Objective: Peripheral biomarker studies in schizophrenia are insufficient to correspond to whether inflammatory markers are trait- or state-related. The main objective of this study was to compare novel biomarkers C-reactive protein/albumin ratio (CAR), neutrophil/albumin ratio (NAR), and complete blood count-derived inflammatory markers; neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), monocyte/lymphocyte ratio (MLR), red-cell distribution width (RDW), and mean platelet volume (MPV) between patients with acutely exacerbated and remitted schizophrenia and healthy controls.

Methods: Anonymous data of a total of 618 patients with schizophrenia (179 in remission, 439 with acute exacerbation) and 445 psychiatrically and medically healthy subjects admitted to outpatient units were included. One-way ANOVA with Tukey's HSD post-hoc test, Pearson's correlation test, receiver operating characteristic analysis, and binomial logistic regression analysis were performed.

Results: CAR, NAR, NLR, PLR, MLR, RDW, MPV values were found higher in patients with schizophrenia than in healthy subjects. Except for NAR (p=0.007), none of the markers differed between acute exacerbation and remission. As a cut-off value of CAR, 0.388 differentiated patients with schizophrenia from controls (sensitivity 81%, specificity 81%). CAR, NAR, and MPV significantly predicted the diagnosis of schizophrenia.

Conclusion: CAR and NAR are reliable biomarkers of inflammation and a combination of inflammatory markers including CAR and NAR could be used to reflect the increased inflammatory status in schizophrenia, regardless of relapse or remission.

Keywords: C-reactive protein-albumin ratio; Inflammation; Relapse; Remission; Schizophrenia; Trait markers.

Figure 1.

Receiver operating characteristic (ROC) curves for the diagnostic ability of CAR and NAR (patient vs. control). ROC curves for CAR and NAR values for the diagnosis of schizophrenia. CAR: AUC 0.882 (95% CI=0.863 to 0.902), p<0.001; NAR: AUC 0.741 (95% CI=0.712 to 0.770), p<0.001. AUC: area under the ROC curve, CAR: C-reactive protein/albumin ratio, NAR: neutrophil/albumin ratio.