The serum C-reactive protein to prealbumin ratio and fibrinogen to prealbumin ratio are two relevant indicators for evaluating the disease activity of ankylosing spondylitis

Abstract

The C-reactive protein to prealbumin ratio (CPR) and fibrinogen to prealbumin ratio (FPR) in serum are two emerging biomarkers. The purpose of this study is to explore the relationship between these two markers and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Scores (ASDAS). A total of 163 patients with AS and 120 healthy examinees were included in this study. The t-test and Mann-Whitney U ranking test were used to analyze the differences between groups. The spearman-test was used to analyze the correlation between erythrocyte sedimentation rate (ESR), c-reactive protein (CRP), fibrinogen (Fib), prealbumin (PAlb), CPR, FPR, and AS disease activity in the test group. We generated the receiver operating characteristic curves (ROC) of CPR and FPR and determined the discriminating ability by calculating the area under the curve (AUC). Compared with the healthy group, ESR ( p < 0.001), CRP ( p < 0.001), Fib ( p < 0.001), CPR ( p < 0.001), and FPR ( p < 0.001) of AS patients were significantly increased, while PAlb was significantly reduced. CPR and FPR were more correlated to ASDAS-CRP. CPR was positively correlated with CRP, ESR, BASDAI, and ASDAS-CRP in AS patients ( r = 0.959, p < 0.001, r = 0.717, p < 0.001, r = 0.704, p < 0.001, r = 0.763, p < 0.001). FPR was positively correlated with CRP, ESR BASDAI, and ASDAS-CRP in AS patients ( r = 0.779, p < 0.001, r = 0709, p < 0.001, r = 0.551, p < 0.001, r = 0.763, p < 0.001). ROC showed that the AUC levels of CPR and FPR were high (AUC = 0.952 and AUC = 0.893). CPR and FPR are two promising new biological indicators for assessing disease activity in AS patients.