Background Methotrexate (MTX) is widely used in the treatment of psoriasis and psoriatic arthritis (PsA). To prevent MTX-induced adverse events dermatological MTX guidelines advise a higher number and frequency of blood tests than rheumatological guidelines (1,2). These differences are not based on evidence indicating a higher risk for patients with psoriasis compared to PsA.
Objectives Compare the effects of MTX monitoring strategies by rheumatologists and dermatologists.
Methods Patients with psoriasis or PsA in a Dutch teaching hospital. Inclusion criteria: start methotrexate (MTX) between 2006 and 2012 and scheduled follow-up by dermatologist or rheumatologist. Exclusions: incomplete availability of lab data. Start and stop dates and dosing of MTX and folic acid, reasons for withdrawal of MTX, numbers and results of laboratory tests performed for MTX safety, occurrence of any serious adverse event (SAE) were retrieved from electronic records.
Results PsA patients used higher initial and maximum doses of MTX and folic acid, but psoriasis patients had a higher frequency of abnormal liver function tests, resulting in a striking difference in withdrawal of MTX (Table). In PsA MTX was more often withdrawn for remission, and less frequently for ineffectiveness leading to longer drug survival in the first course of treatment. There were no differences in the occurrence of SAE or death between these groups. Hospital admissions related to infection were recorded in 6 (3.1%) PsA vs 4 (2.1%) psoriasis patients.
Conclusions Monitoring by dermatologists resulted in more abnormal liver function tests and shorter drug survival of MTX. The monitoring strategy by rheumatologists was not associated with increased SAEs. This supports the safety of current rheumatological guidelines and suggests reconsideration of a higher number of liver function tests in dermatological guidelines.
Menter A, Korman NJ, Elmets C et al. Guidelines of care for the management of psoriasis and psoriatic arthritis. J Am Acad Dermatol. http://dx.doi.org/10.1016/j.jaad.2009.03.027.
Barker J, Horn EJ, Lebwohl M et al. Assessment and management of methotrexate hepatotoxicity in psoriasis patients: Report from a consensus conference to evaluate current practice and identify key questions toward optimizing methotrexate use in the clinic. J Eur Acad Dermatol Venereol 2011;25:758–64.
Disclosure of Interest None declared