The lack of association between cumulative MTX dose and liver fibrosis in PsA: a cohort study.

Abstract

Evidence for the association between MTX use and liver fibrosis in PsA remains inconclusive. We aimed to explore the frequency of liver fibrosis in PsA and identify associated factors including cumulative MTX dose and metabolic features. We analysed data from a prospective observational PsA cohort. We calculated the aspartate aminotransferase to platelet ratio index (APRI), a non-invasive marker commonly used to assess fibrosis in patients with liver diseases. A cut-off of >0.7 was used to denote liver fibrosis. We conducted univariable and multivariable generalized estimating equations (GEEs) analysis to assess the impact of cumulative MTX dose and metabolic factors on liver fibrosis, adjusting for confounders such as demographic characteristics, comorbidities and medications. One thousand three hundred and fourteen patients were included in the study, with a mean age of 44.4 (S.D. 13.1) at baseline (clinic entry). Of these, 375 (28.5%) patients were receiving MTX at baseline, while 763 (58.1%) had ever received the medication. Forty-four (3.3%) patients fulfilled the definition of liver fibrosis per APRI at baseline, while 154 (11.7%) developed liver fibrosis during follow-up at a median of 5.6 [IQR: 2.0-11.1] years from baseline. In the multivariable model, adjusted for confounders, cumulative MTX dose was not independently associated with liver fibrosis (OR 0.99, 95% CI 0.98-1.01). However, higher BMI (OR 1.03, 95% CI 1.00-1.05) and diabetes mellitus (OR 5.03, 95% CI 2.19-11.56) showed a significant association. Metabolic factors, rather than the cumulative MTX dose, are associated with liver fibrosis in PsA.