According to a meta-analysis of RA, there was a positive, weak correlation between circulating VEGF levels and disease activity (DAS-28; ES 0.33, 95% CI 0.22–0.44, P < 0.0001, pooled r = 0.32), ESR (ES 0.35, 95% CI 0.18–0.51, P < 0.0001; summary r = 0.34), and CRP (CRP; ES 0.38, 95% CI 0.24–0.52, P < 0.0001; summary r = 0.36) [13]. Here, CRP is linked to rheumatoid arthritis.