Cumulative methotrexate dose is not associated with liver fibrosis in patients with a history of moderate-to-severe psoriasis.

Background: There are established risk factors for liver fibrosis (LF), but data on the impact of methotrexate on LF in patients with psoriasis are lacking.

Objectives: This cross-sectional study aimed to determine the prevalence of LF in patients with psoriasis and to evaluate the relationship between LF, cumulative methotrexate dose and other LF risk factors.

Methods: Adults with a history of moderate-to-severe chronic plaque psoriasis were recruited between June 2020 and March 2021. Patients underwent transient elastography to evaluate LF. Three values for liver stiffness measurement (LSM) were assessed, indicating mild or worse LF (≥ 7 kPa), moderate or worse LF (≥ 7.9 kPa) and advanced LF (≥ 9.5kPa). Cumulative methotrexate dose and other potential risk factors for LF were assessed.

Results: Overall, 240 patients were recruited and 204 participants with valid LSM values were included in the analysis [median age 48 years [interquartile range (IQR) 37-57]; 51% female sex; 56% body mass index (BMI) ≥ 30 (kg m-2) and a median Alcohol Use Disorders Identification Test (AUDIT) score of 4 (IQR 1-7, 23% score ≥ 8)]. In total, 91% had received methotrexate [median duration 36 months (IQR 14-78)]. Prevalence of LF was 36%, 25% and 17% using LSM ≥ 7 kPa, ≥ 7.9 kPa and ≥ 9.5 kPa, respectively. There was no association between cumulative methotrexate dose [median 2.16 (IQR 0.93-5.2)] and continuous LSM values [unstandardized coefficient 0.16, 95% confidence interval (CI) -0.49 to 0.82, P = 0.626] or using the categorical LSM cutoff values: ≥ 7 kPa [unadjusted odds ratio 1.06 (95% CI 0.97-1.15), P = 0.192], ≥ 7.9 kPa [unadjusted odds ratio 1.03 (95% CI 0.94-1.12), P = 0.577] and ≥ 9.5 kPa (unadjusted odds ratio 1.01, 95% CI 0.91-1.12; P = 0.843). 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). BMI ≥ 28, diabetes and metabolic syndrome were shown to be better predictors of LF compared with FIB-4 score.

Conclusions: This study confirms a high prevalence of significant LF in patients with psoriasis. Cumulative methotrexate dose was not associated with LF. Patients with BMI ≥ 28, metabolic syndrome and diabetes are at higher risk for LF. These risk factors may help to identify when a more detailed liver health assessment is needed.