High level of ESR has been found in patients with RA (SMD: 1.22, 95% CI: 0.66 to 1.78; 95% PI: 0.11 to 2.06; I2 = 83%, P for heterogeneity = 0.003), while the pooled SMD from 5 trials revealed ESR levels was decrease in RA patient who received anti-inflammation therapy (SMD: -1.98, 95% CI: − 3.23 to −.0.74; I2 = 92%, P for heterogeneity < 0.001) (Fig. 3). This evidence concerns the gene ESR1 and rheumatoid arthritis.