Linkage of Calprotectin with Inflammation, Activity and Treatment Response of Rheumatoid Arthritis: A Meta-Analysis

Aim: This meta-analysis aimed to investigate the clinical value of calprotectin in rheumatoid arthritis (RA) patients. Methods: The data regarding blood calprotectin levels in RA patients were retrieved from PubMed, Embase, Web of Science and Cochrane databases. Results: Thirty-one eligible articles were included. Calprotectin was increased in RA patients compared with healthy controls (mean difference [MD] = 1.48, 95% CI: 1.16–1.79). Calprotectin was positively associated with C-reactive protein (correlation coefficient [CC] = 0.58, 95% CI: 0.53–0.63) and disease activity score (CC = 0.48, 95% CI: 0.38–0.58) in RA patients. Interestingly, calprotectin showed an increased trend in RA responders compared with nonresponders, but without statistical significance (MD = 0.38, 95% CI: -0.09–0.85). Conclusion: Blood calprotectin relates to disease risk, inflammation and activity in RA patients.