Transient Elastography Deemed Reliable Method to Detect Liver Fibrosis in Patients with PsO Treated with MTX

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Recent research demonstrated transient elastography was a reliable and superior method to detect liver fibrosis among a cohort of Chinese patients with psoriasis (PsO) being treated with methotrexate compared with the total cumulative dose of methotrexate (≥ 3.5 g) method.

Therefore, a liver biopsy should be reserved for high-risk patients or those with liver stiffness of ≥ 11.7 kilopascals (kPa) on transient elastography, according to a study published in the Hong Kong Academy of Medicine.¹

Although methotrexate is an effective, safe, and cost-effective immunosuppressive drug for patients with PsO and psoriatic arthritis (PsA), prolonged use may cause liver fibrosis and fatty changes without altering liver enzymes. These changes might be due to the production of extracellular adenosine.² As liver biopsy—a gold standard for detecting liver injury among this patient population—is risky and invasive, transient elastography could be a safer option.

“Transient elastography is a non-invasive method for assessing liver ‘hardness’ or stiffness that involves measuring the velocity of a vibration wave (ie, a shear wave) when travelling to a particular depth inside the liver, based on the principle that the wave velocity is greater in fibrotic tissue than in normal liver tissue,” wrote a group of international investigators predominantly associated with the University of Hong Kong. “This technique has been used as a screening tool for liver cirrhosis in various conditions. In contrast to liver biopsy, transient elastography allows the simultaneous assessment of a larger sampling area, is easily reproducible, and has low inter-observer variability and a low failure rate (<5%).”

Investigators evaluated the performance of transient elastography in methotrexate-induced liver fibrosis compared with liver biopsy in a cohort of adult Chinese patients with clinically diagnosed PsO. Liver stiffness was measured using transient elastography. Exclusion criteria included conditions that could influence transient elastography performance, positive viral hepatitis carrier status, and known liver cirrhosis. Biopsy was conducted when liver stiffness was ≥ 7.1 kPa or if the total cumulative dose of methotrexate was ≥ 3.5 g.

A total of 228 patients were ultimately recruited for the study, of which 34 met the inclusion criteria. Of these, approximately one-fourth (26.5%) had significant liver fibrosis. The area under the receiver operating characteristic curve was .76 (95% confidence interval [CI] = .59 — .93; P = .021), which demonstrated the satisfactory performance of transient elastography in detecting liver fibrosis.

Using a cut-off value of 7.1 kPA for liver stiffness, results yielded 100% sensitivity and 68% specificity among this patient population. Although liver fibrosis was significantly correlated with obesity and diabetes status, as defined by a body mass index of ≥ 30 kg/m2, waist circumference ≥ 138 cm, and glycated hemoglobin level ≥ 7.8%, it was not linked with the total cumulative dose of methotrexate or the duration of methotrexate use.

Investigators noted the small sample size as a limitation of the study. A larger sample size could be beneficial to draw definitive conclusions, despite liver fibrosis being generally uncommon in patients with PsO receiving methotrexate.

“When considering liver biopsy to rule out the possibility of clinically significant liver fibrosis, transient elastography-based liver stiffness measurements provide superior reference information, compared with the total cumulative dose of methotrexate,” investigators concluded. “Patients with high body mass index, body weight, and abdominal obesity have a higher risk of liver fibrosis. Therefore, these factors should be considered when monitoring methotrexate-related liver fibrosis in psoriasis patients.”

References

1. ^{Wong CSM, Mak LLY, Lee VKH, et al. Detection of significant liver fibrosis in Chinese psoriasis patients receiving methotrexate: a comparison between transient elastography and liver histology. Hong Kong Med J. 2024;30(2):110-119. doi:10.12809/hkmj2210364}
2. ^{Themido R, Loureiro M, Pecegueiro M, Brandão M, Campos MC. Methotrexate hepatotoxicity in psoriatic patients submitted to long-term therapy. Acta Derm Venereol 1992;72:361-4}