Methotrexate does not increase the risk of liver fibrosis in patients with rheumatoid arthritis: assessment by ultrasound elastography (ARFI-MetRA study).

Objectives: Only limited data are available on the risk of liver fibrosis in patients with rheumatoid arthritis on long-term methotrexate treatment. To assess the risk of liver fibrosis in patients with rheumatoid arthritis treated with methotrexate, non-invasive, ultrasound-based elastography [acoustic radiation force impulse (ARFI) imaging] was applied.

Methods: In total, 119 patients were assessed using acoustic radiation force impulse (ARFI) imaging between July 2018 and April 2019. In a cross-sectional, single-centre study design, ARFI scores were compared between patient subgroups with (n = 65) and without (n = 54) methotrexate exposure. The main outcome variable was the mean fibrosis score as measured by the ARFI method. The mean shear wave velocity was calculated from 10 valid ARFI measurements for each patient. Inferential statistical analyses (between group) were performed using ANOVA for independent samples in the case of continuous outcome variables.

Results: Sixty-five patients with and fifty-four patients without MTX exposure were assessed using the ARFI elastography method. Participating patients on MTX medication (1.113 m/s) showed ARFI scores that were comparable to those of participants without MTX exposure (1.062 m/s); P = 0.228. The mean cumulative dose in the group of MTX-exposed patients was 3602 mg.

Conclusion: The mean value of the repeated determination of liver density using ARFI imaging did not differ significantly between the MTX-exposed and MTX-naive patients with RA. No increased rate of liver fibrosis was found among RA patients treated with MTX.