Liver biopsy in psoriatic arthritis to detect methotrexate hepatotoxicity

The use of methotrexate in the treatment of psoriatic arthritis is associat ed with risk of hepatotoxicity. However, monitoring of liver-associated enz ymes often lacks sensitivity, and guidelines for serial liver biopsies in p soriatic arthritis are not yet well established. We performed a retrospecti ve review of all patients with psoriatic arthritis receiving methotrexate w ho were enrolled in the disease-modifying anti-rheumatic drug clinics (DMAR D clinics) at the Air Force and Army hospitals in San Antonio, Texas. Infor mation was obtained regarding methotrexate regimen, liver-associated enzyme results, and liver biopsy results. Thirty psoriatic arthritis patients wer e taking methotrexate in the DMARD clinics. Seventeen patients had a total of 21 biopsies. Biopsies were performed for surveillance dictated by cumula tive dose. Liver biopsies were graded on Roenigk scale of I-IV where I is m ild steatosis, IT is moderate steatosis, Ma is mild fibrosis, IIIb is sever e fibrosis, and IV is cirrhosis. Ten biopsies were grade I, 5 were grade II , 5 were grade IIIa, I was grade IIIb, and none were grade IV. In this very small retrospective study, regular monitoring of liver-associa ted enzymes did not correlate with histologic deterioration in our patients . Until prospective studies are performed, we suggest that routine liver bi opsies are necessary to monitor for methotrexate hepatotoxicity in psoriati c arthritis.