Calprotectin in spondyloarthritis: A systematic review and meta-analysis

•Serum and fecal calprotectin were increased in SpA patients.•Level of serum or fecal calprotectin was associated with CRP, ESR, BASDAI and BASFI.•Serum and fecal calprotectin could act as biomarkers for SpA. There is still an unmet need for a simple and reliable biomarker for diagnosis and disease activity of spondyloarthritis. Recent studies indicated that calprotectin could act as a biomarker for spondyloarthritis. Therefore, this systematic review and meta-analysis aims to evaluate the levels of serum and fecal calprotectin in spondyloarthritis and the associations with disease activity. PubMed, Web of Science and Cochrane Library were comprehensively searched from inception to July 1st, 2019. The pooled standard mean differences (SMDs) were used to estimate the differences of the levels of serum and fecal calprotectin between spondyloarthritis patients and controls. Spearman correlation coefficients were used for evaluating the associations between the levels of serum and fecal calprotectin and disease activity of spondyloarthritis patients. The use of fixed-effect or random-effects model depended on heterogeneity. Among 257 searched studies, 20 studies were finally included for analysis. Serum and fecal calprotectin were both significantly increased in spondyloarthritis patients compared to matched controls (SMD = 1.49, 95% CI = 0.91 to 2.08; SMD = 2.29, 95% CI = 0.25 to 4.33). The pooled correlation coefficients between serum or fecal calprotectin and CRP, ESR, BASDAI and BASFI were 0.353, 0.228, 0.225, 0.131 and 0.185, 0.163, 0.280, 0.196 respectively. Our study indicated that serum and fecal calprotectin were significantly increased in spondyloarthritis patients, and associated with disease activity. Serum and fecal calprotectin were potential biomarkers for the diagnosis and disease activity of spondyloarthritis.