At the baseline, YKL-40 concentration in the DMARD-naïve RA patients was 57 ± 37 ng/ml (mean ± SD, n = 88) and there was no differences between females and males (55 ± 37 ng/ml, n = 60 vs 61 ± 38 ng/ml, p = 0.43). Here, CHI3L1 is linked to rheumatoid arthritis.