C-Reactive Protein-to-Albumin Ratio: A Novel Inflammatory Marker and Disease Activity Sign in Early Rheumatoid Arthritis

Abstract

Abstract Objective A novel inflammation-based score, C-reactive protein (CRP)-to-albumin ratio (CAR), has been shown to have an association with the inflammatory status in several diseases. We aimed to analyse the association between CAR and disease activity in patients with early rheumatoid arthritis (RA) and to determine the cut-off value of CAR in early and established RA. Methods A total of 177 patients with RA and 111 age and gender-matched healthy controls were included in this study. Cases with a disease duration of less than 1 year were classified as early RA. Serum albumin, CRP, erythrocyte sedimentation rate (ESR), Disease Activity Score-28 (DAS-28-ESR), Clinical Disease Activity Index (CDAI) and Health Assessment Questionnaire (HAQ) scores were recorded. Results CAR was 2.44 (0.21–30.83) in the RA group and 0.45 (0.21–10.47) in the control group (p<0.001). Eighty-seven (49.15%) of the RA cases were classified as early RA. The analyses indicated that the ESR, CRP and CAR values were higher in patients with early RA than in those with established RA and controls. CAR was correlated with albumin, CRP, ESH, DAS-28 and HAQ scores in both early RA and established RA groups. The receiver operating characteristic curves revealed a CAR cut-off value of 2.67 (80% sensitivity and 85% specificity) and 1.63 (77% sensitivity and 72% specificity) for the prediction of early and established RA, respectively. Conclusion CAR, a formulated ratio, has been described as a predictor for disease activity in patients with early RA as well as in those with established RA. However, CAR has higher sensitivity and specificity for early RA than for established RA.