Liver fibrosis is independent of methotrexate use in patients with moderate-to-severe psoriasis

Abstract Methotrexate has been implicated for liver disease in patients with psoriasis for many years. Liver fibrosis (LF) has various established risk factors, but data on the impact of methotrexate on LF in patients with psoriasis are lacking. This cross-sectional cohort study aimed to determine the prevalence of LF using noninvasive LF markers in patients with psoriasis, and to evaluate the relationship between LF and the cumulative dose of methotrexate and other liver disease risk factors. Adults with moderate-to-severe chronic plaque psoriasis diagnosed by a dermatologist, who were selected for a LF assessment, were recruited from dermatology clinics in a tertiary centre between June 2020 and March 2021. Data were recorded as part of standard clinical care and at the time of recruitment. Patients underwent transient elastography to evaluate LF. Three values for liver stiffness measurement (LSM) were used, indicating ≥ mild LF (≥ 7 kPa), ≥ moderate LF (≥ 7.9 kPa) and ≥ advanced LF (≥ 9.5 kPa). Both continuous and categorical LSM values were used for evaluation. A total of 225 patients were included [median age 48, interquartile range (IQR) 37–57, 51% female]. Fifty-six per cent had a body mass index (BMI) ≥ 30 kg m−2, and the median alcohol use disorders identification test (AUDIT) score was 4 (IQR 1–7, 23% score ≥ 8). Ninety-one per cent had received methotrexate for a median duration of 36 months (IQR 14–78). Prevalence rates of LF were 31%, 21% and 13% using LSM ≥ 7 kPa, ≥ 7.9 kPa and ≥ 9.5 kPa, respectively. There was no association between methotrexate and continuous LSM values [unadjusted coefficient 0.16, 95% confidence interval (CI) 0.49–0.82; P = 0.63] or using the categorical LSM cutoff values: 7 kPa (unadjusted coefficient 1.06, 95% CI 0.98–1.15; P = 0.19), 7.9 kPa (unadjusted coefficient 1.03, 95% CI 0.94–1.12; P = 0.58) and 9.5 kPa (unadjusted coefficient 1.01, 95% CI 0.91–1.12; P = 0.84). Similarly, no significant relationship was found when adjusting for other risk factors for LF. The following risk factors were associated with higher LSM values: BMI (P < 0.001), waist circumference (P < 0.001), metabolic syndrome (P < 0.001), AUDIT score (P = 0.020) and Fib-4 score (P = 0.03). This study confirms a high prevalence of significant LF in patients with moderate-to-severe psoriasis. More importantly, it shows that cumulative methotrexate was not associated with LF, and other risk factors including BMI, waist circumference, metabolic syndrome, alcohol intake and Fib-4 score are important predictors for LF. The findings suggest that these risk factors should be assessed in this group of patients to identify patients requiring regular liver health monitoring. Further research is needed to determine whether methotrexate contributes to the progression of LF in the context of pre-existing LF.