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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12891-016-1213-6) contains supplementary material, which is available to authorized users.