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Objective: Several seminal studies have suggested that a combination therapy of biologics with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) improve disease outcomes in rheumatoid arthritis (RA). Hence, most guidelines reflect this practice. It has also been shown that methotrexate (MTX) at a dose of 8-10 mg/week is perhaps sufficient to achieve better outcomes in early RA. However, it is not clear whether this strategy enhances biologic retention in the patients with established RA. We present a real-world retrospective study to investigate whether csDMARD co-prescription improves biologic retention and the optimal dose to preserve such response.
Materials and Methods: All patients prescribed biologic therapy for RA at our center between 2003 and 2017 were identified through the departmental database. They were split into five groups based on a weekly MTX dose (≤7.5 mg, 10-17.5 mg, ≥20 mg), other csDMARD prescription, or biologic monotherapy. The one-way analysis of variance model for independent values was utilized to ascertain the significance of data. The Mann-Whitney two-tailed U test was employed to determine the significance of relationship between the monotherapy group and other arms. The significance level was predefined at 0.05.
Results: A total of 168 patients with 198 biologic events were included. The mean age was 59.4 years (range, 24-90 years). 78% were women. The mean disease duration was 155.6 months (range, 15-491). There was a statistically significant difference (p=0.03) in biologic retention among the five arms. Compared to monotherapy, the data remained significant for ≥20 mg MTX and csDMARD groups; however, the biologic retention in the other two MTX arms was not significant. There was no significant relationship among groups for DAS28 improvement (p=0.24).
Conclusion: Our results suggest that to improve biologic retention, the MTX dose should be increased to 20 mg a week or more, and, in people with MTX intolerance, csDMARDs co-presciption can be an alternative strategy. Maintenance with a low-to-moderate MTX dose can lead to poorer retention rates.
Cite this article as: Mothojakan N, Janki G, Nisar M. Does biologic survival depend on co-prescribed methotrexate dose in established rheumatoid arthritis? Eur J Rheumatol 2020; 7(1): 21-5.