We set out in this study to demonstrate the adverse effect profile of methotrexate when used in the treatment of rheumatoid arthritis (RA) and psoriatic arthritis (PsA) in a district general hospital population, and to investigate the effect of alcohol consumption in these patients.
A prospective evaluation of 550 RA patients and 69 PsA patients was undertaken, controlling for confounding factors. Systematically randomised patients were further analysed regarding alcohol consumption. A transaminase level of three times the upper limit of normal on two or more occasions was taken to indicate hepatic injury.
Gastrointestinal disturbance was the predominant adverse effect in RA patients (9.8%); hepatic disturbance was the most frequent in PsA patients (14.5%). Both groups had hepatic enzyme elevation; PsA patients were at significantly greater risk of elevated transaminases than RA patients (14.5% vs 7.5%, respectively, chi2 = 4.017). Alcohol consumption did not correlate with hepatic injury (mean 5.15 vs 6.6 alcohol units/week consumed by RA and PsA patients, respectively).
Our data show methotrexate-treated PsA patients have a higher incidence of hepatotoxicity compared with methotrexate-treated patients with RA. It is proposed that psoriatic patients may be inherently more susceptible to methotrexate hepatotoxicity than are rheumatoid patients.