Hepatotoxicity rates do not differ in patients with rheumatoid arthritis and psoriasis treated with methotrexate

Objective. MTX hepatotoxicity is considered to occur more frequently in patients with psoriasis than in patients with RA. However, toxicity guidelines are based on reports from studies with small sample sizes and limited follow-up periods. The current study's objective was to examine the long-term risk of MTX hepatotoxicity based on a database review of patients with RA or psoriasis, and to examine whether the two populations differed. Methods. We conducted a retrospective cohort review among members of a large health maintenance organization (HMO) in Israel who were diagnosed with either RA (n=119) or psoriasis (n=690) and who had purchased at least one dose of MTX. Liver function analyses were performed serially in these patients during the follow-up. All abnormal assays were recorded in the computerized database of the HMO. Results. Both groups had hepatic enzyme elevation; the pre-disposing factors predictive of liver damage were female gender and a higher cumulative dose of MTX (hazard ratios, 1.46 and 1.07, respectively, P < 0.001). Age, concurrent diseases and type of disease had no influence on susceptibility to liver damage. No statistically significant difference was detected in any abnormal liver function test among patients with either RA or psoriasis. Conclusion. Our study did not corroborate previous findings of significant differences between psoriasis patients and RA patients concerning susceptibility to hepatotoxicity from MTX therapy. The only significant factor predicting a higher risk of hepatic damage was female gender.