Liver fibrosis in patients with psoriasis and psoriatic arthritis on long-term, high cumulative dose methotrexate therapy.

OBJECTIVES: Dermatologists and rheumatologists have differed in their use of serial liver biopsy and liver function tests (LFT) to monitor the risk of hepatic fibrosis in long-term MTX therapy. It is judged safe to monitor LFT only in RA. Whilst there are few studies in PsA to justify this approach, it is widely used in rheumatology practice. The study aimed to assess prevalence of hepatic fibrosis in both psoriasis and PsA patients on long-term MTX therapy.

METHODS: A prospective study of 54 patients with psoriatic disease had a liver biopsy according to dermatology guidelines on long-term MTX treatment with full assessment of risk factors. Previously, monitoring these patients was in accordance with ACR guidelines with 3-monthly LFT.

RESULTS: MTX treatment duration was a mean of 6.9 years, with a mean cumulative dose of 4396 mg. There were no cases of advanced fibrosis or of cirrhosis and mild early fibrosis in 11 (22%) patients. The presence of early mild changes was related to the number of risk factors that the patient had for hepatic fibrosis [also the risk factors for non-alcoholic steatohepatitis (NASH)]. Pro-collagen 3 N-terminal peptide (PIIINP) was unhelpful in PsA and frequently elevated despite normal liver biopsy.

CONCLUSIONS: Despite other risk factors for NASH, monitoring for hepatic fibrosis using serial liver function and ACR guidelines tests alone as in RA appears safe in psoriasis and PsA. Liver biopsy ought to be considered to assess the liver if LFT are persistently elevated. PIIINP is misleading in active PsA.