Correlation between C-Reactive Protein to Albumin Ratio and Disease Activity in Patients with Axial Spondyloarthritis
Zhong Zheng, Yukai Huang, Yuqi Liu, Junming Chen, Meng Liu, Qidang Huang, Shaoling Zheng, Xin Guo, Weiming Deng, Li T
Abstract
Background. The C-reactive protein (CRP) to albumin (ALB) ratio (CAR) has emerged as a novel inflammatory biomarker. This study was designed to investigate the role of CAR in the disease activity of axial spondyloarthritis (axSpA). Methods. A total of 241 patients and 61 healthy controls were retrospectively enrolled in this study. AxSpA patients were further divided into the inactive group ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>n</a:mi> <a:mo>=</a:mo> <a:mn>176</a:mn> </a:math> ) and active group ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>n</c:mi> <c:mo>=</c:mo> <c:mn>65</c:mn> </c:math> ) according to Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) cutoff value of 4. Laboratory data and clinical assessment indices were recorded. Spearman’s correlation analysis, receiver operation characteristic (ROC) curve analysis, and binary logistic regression analysis were performed. Results. In axSpA patients, CAR was significantly higher than the healthy group ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mi>P</e:mi> <e:mo><</e:mo> <e:mn>0.001</e:mn> </e:math> ). Similarly, axSpA patients in the active group had higher CAR than the inactive group ( <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"> <g:mi>P</g:mi> <g:mo><</g:mo> <g:mn>0.001</g:mn> </g:math> ). Besides, CAR was positively correlated with erythrocyte sedimentation rate (ESR) ( <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M5"> <i:mi>r</i:mi> <i:mo>=</i:mo> <i:mn>0.704</i:mn> </i:math> , <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" id="M6"> <k:mi>P</k:mi> <k:mo><</k:mo> <k:mn>0.001</k:mn> </k:math> ), CRP ( <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" id="M7"> <m:mi>r</m:mi> <m:mo>=</m:mo> <m:mn>0.996</m:mn> </m:math> , <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" id="M8"> <o:mi>P</o:mi> <o:mo><</o:mo> <o:mn>0.001</o:mn> </o:math> ), BASDAI ( <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" id="M9"> <q:mi>r</q:mi> <q:mo>=</q:mo> <q:mn>0.329</q:mn> </q:math> , <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" id="M10"> <s:mi>P</s:mi> <s:mo><</s:mo> <s:mn>0.001</s:mn> </s:math> ), and Bath Ankylosing Spondylitis Functional Index (BASFI) ( <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" id="M11"> <u:mi>r</u:mi> <u:mo>=</u:mo> <u:mn>0.330</u:mn> </u:math> , <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" id="M12"> <w:mi>P</w:mi> <w:mo><</w:mo> <w:mn>0.001</w:mn> </w:math> ). ROC curve analysis suggested that the area under the curve (AUC) of CAR for axSpA of the active group was 0.701, which was higher than that of CRP and ESR. The optimal cutoff point of CAR for axSpA of the active group was 0.3644, with a sensitivity and specificity of 58.5% and 79.0%. Binary logistic analysis results revealed that CAR was an independent predictive factor for axSpA disease activity ( <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" id="M13"> <y:mtext>odds</y:mtext> <y:mtext> </y:mtext> <y:mtext>ratio</y:mtext> <y:mo>=</y:mo> <y:mn>4.673</y:mn> </y:math> , 95% CI: 1.423-15.348, <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" id="M14"> <ab:mi>P</ab:mi> <ab:mo>=</ab:mo> <ab:mn>0.011</ab:mn> </ab:math> ). Conclusions. CAR was increased in axSpA and axSpA of the active group. CAR may be a novel and reliable indicator for axSpA disease activity.