Background: Aiming at rapid decrease of disease activity, there has been a trend to start with higher doses of methotrexate (MTX) in patients newly diagnosed with rheumatoid arthritis (RA), both as monotherapy and in combination with other antirheumatic drugs. We aimed to study the relationship between clinical response and MTX dose as monotherapy or combination therapy in patients with early RA.
Methods: Disease-modifying anti-rheumatic drug (DMARD)-naive patients with early RA, from a large international observational database, the METEOR database, were selected if MTX was part of their initial treatment. Patients were divided into four groups: MTX monotherapy, MTX + convention synthetic (cs)DMARDs, MTX + glucocorticoids or MTX + biologic (b)DMARDs. MTX dose was dichotomized: low dose ≤10 mg/week; high dose ≥15 mg/week. Linear mixed model analyses for the Disease Activity Score (DAS), DAS in 28 joints (DAS28) and Health Assessment Questionnaire (HAQ) were performed in each medication group, with MTX dose and time as covariates. Outcomes were assessed from baseline until 3-6 months follow up. Associations were adjusted for potential confounding by indication using propensity score (PS) modelling.
Results: For patients starting MTX monotherapy (n = 523), MTX + csDMARDs (n = 266) or MTX + glucocorticoids (n = 615), the PS-adjusted effects of MTX dose (high versus low) on the DAS, DAS28 and HAQ were small and not clinically meaningful. Patients starting MTX + bDMARDs were disregarded due to low numbers (n =11).
Conclusions: In patients newly diagnosed with RA, no clinical benefit of high compared to low initial MTX doses was found for MTX monotherapy or for MTX combination therapy with csDMARDs or glucocorticoids.
Keywords: Combination therapy; Dose; Methotrexate; Outcome measures; Rheumatoid arthritis.