Liver injury in long-term methotrexate treatment in psoriasis is relatively infrequent

Methotrexate-induced liver damage in psoriasis has led to dermatologic guidelines that stipulate monitoring of liver injury by means of serial liver biopsies. Recent literature data suggest that methotrexate may be considerably less hepatotoxic than previously assumed. To evaluate prevalence and development of liver injury in methotrexate treated psoriasis. Retrospective chart review (1976-2005). Hundred and twenty-five patients (F58/M67; mean age 45.0, SD 12.7 years) received a median cumulative methotrexate dose of 2113 mg (range 180-20 235) over a median period of 228 weeks (range 16-1763). Two hundred and seventy eight liver biopsies were analysed and 71% were classified as Roenigk grade I, 14% as Roenigk II, 14% grade IIIa, 2% grade IIIB and 2% grade IV. Liver injury was not associated with cumulative dose, weekly prescribed dose, age or duration of treatment. Obesity and diabetes were significant risk factors for liver injury. A total of 68 patients had multiple biopsies, 3% improved, 72% did not change and in 25% liver histology deteriorated. The majority of cases (84%) that progressed to Roenigk 2 had a cumulative dose of 1500-6000 mg. Methotrexate-related liver injury is less frequent than previously thought and mostly occurred at cumulative dose of < 6000 mg. Diabetes and being overweight are significantly correlated with liver injury.