The rapid kinetics of optimal treatment with subcutaneous methotrexate in early inflammatory arthritis: an observational study

Anna O’Connor, Carter Thorne, Hyeon Kang, Diane Tin, Janet E. Pope

Methotrexate (MTX) is standard treatment for RA. Absorption is better in subcutaneous MTX (scMTX), which may impact speed of onset. In RA, earlier time to remission improves long-term results. Our objectives were to determine rapidity of response of subcutaneous methotrexate in early rheumatoid arthritis. The change in several disease activity measures (including DAS28) from 0 to 6 weeks (early period) and 6 to 12 weeks (late period) was compared. The proportion achieving DAS28/CDAI/SDAI remission and/or low disease activity state was also compared. One hundred three patients were included from a single site between 2008 and 2014. All received MTX (98.0 % scMTX, 98 % 25 mg/week). There were no dropouts. There was a significantly greater early change in DAS28 (-1.9 vs. -0.2, p < 0.00); this effect was seen for several outcome measures. By 6 weeks, 59 % had achieved either DAS28 remission or low disease activity state, with 74 % achieving either state by 12 weeks. There were a larger proportion of patients achieving CDAI and DAS28 remission in the early versus late period (p < 0.0002 for both). There was significant improvement when using combination MTX and HCQ, however sample size was small (n = 9). The use of intra-articular steroids with MTX yielded the most disease measures that demonstrated early significant improvement. Subcutaneous MTX is rapid, as the change in many disease activity scores was significantly greater between 0-6 weeks compared to 6-12 weeks. Combination MTX + HCQ gave added value, although generalizability is limited by combination cohort sample size. Intra-articular steroid injections may contribute to the early effect.