YKL-40 Levels in Rheumatoid Arthritis and Their Correlation with Disease Activity: A Meta-analysis

ABSTRACT

OBJECTIVE: To examine the relationship of serum/plasma YKL-40 levels with rheumatoid arthritis (RA) and their correlation with RA activity and rheumatoid factor (RF) level. METHODS: We performed a meta-analysis comparing the serum/plasma YKL-40 levels between patients with RA and controls and examined the correlation coefficients of the circulating YKL-40 level with the RF level and RA activity based on the 28-joint disease activity score (DAS28), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level. RESULTS: Nine studies (707 patients with RA and 1,041 controls) were included in the meta-analysis. The YKL-40 levels were significantly higher in the RA group than in the control group (standardized mean difference [SMD]=1.071, 95% confidence interval [CI]=0.726~1.417, p100) populations. Meta-analysis of correlation coefficients showed a significant positive correlation between the YKL-40 levels and DAS28, ESR, CRP level, and RF level (DAS28 correlation coefficient=0.381, 95% CI=0.044~0.640, p=0.028; RF level correlation coefficient=0.341, 95% CI=0.176~0.487, p<0.001). CONCLUSION: The circulating YKL-40 levels are high in patients with RA and positively correlate with RA activity and RF level.