To explore the significance of the association between treatment with methotrexate (MTX) and liver stiffness in rheumatoid arthritis (RA) patients.
We enrolled 140 consecutive RA patients under MTX treatment (MTX-treated RA; mean treatment duration: 6.2 years; mean MTX cumulative dose: 4.67 g), 33 RA patients naive to MTX (MTX-naive RA) and 100 age and sex-matched healthy blood donors (HD). Liver stiffness was assessed by real time two-dimensional shear wave elastography, with values ≥7.1 Kilopascals (kPa) defining significant liver fibrosis.
kPa values in HD (4.32 ± 0.7) were lower than that in MTX-naive RA (4.92 ± 0.8) and MTX-treated RA (4.85 ± 0.9, p < .0005 for trend). On the contrary, the difference in kPa between MTX-naive and MTX-treated RA was not significant (p = .89). Similarly, liver stiffness was not significantly different across strata of cumulative MTX dose (4.95 ± 0.7 kPa in MTX <1 g, 4.90 ± 1.1 kPa in MTX 1-3 g and 4.80 ± 0.9 in MTX >3 g, p = .610). Significant liver fibrosis was diagnosed in 4 patients in the MTX-treated RA (highest kPa value = 7.6; no liver function test abnormalities or clinical signs of hepatic failure) and in none in both the MTX-naive RA and HD groups (p = .145).
Liver stiffness values, although within the normal range, are significantly higher in RA patients vs. controls, irrespective of MTX treatment. RA patients taking MTX do not have a higher prevalence of significant liver fibrosis when compared to MTX naive RA patients and the general population.