Receiver operating characteristic curves of the MMP-3 ratio for achievement of DAS and US remission at 24 weeks after addition of iguratimod.

A: DAS remission, B: US remission. MMP-3 ratio, the ratio of the serum matrix metalloproteinase 3 levels at baseline to those at 12 weeks; DAS remission, disease activity score in 28 joints <2.6; US remission, total power Doppler ultrasound score <3.