Rheumatology Advance Access originally published online on December 6, 2005
Rheumatology 2006 45(3):361; doi:10.1093/rheumatology/kei199
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LETTER TO THE EDITOR |
Methotrexate induced pancytopenia is rare and concern for it should not limit its use
NYU Hospital for Joint Diseases, New York, NY, USA
Correspondence to: Yusuf.yazici{at}nyumc.org
SIR, I read with interest the article by Lim et al. [1] and feel the need to share our experience of the safety of methotrexate (MTX) in rheumatoid arthritis (RA) patients. The authors report on 25 patients, of whom 19 had RA, who developed pancytopenia while taking MTX. They conclude that ‘MTX-induced pancytopenia is more common than expected and is probably under-reported’.
This conclusion raises some concerns. First, the reference the authors give for the prevalence of haematological toxicity of MTX is from 1985 [2]. Surely the kind of patients using MTX and the timing of MTX use have changed over the last 20 yr and, along with these, the occurrence of adverse events. Secondly, they fail to give the total number of MTX-treated patients seen between 1999 and 2004 in the centre that these 25 patients came from. They give estimates of RA prevalence in their area and an assumption about other patients with other diagnoses using MTX, but the denominator is not given. It is not clear what is used as a comparator when they state that this problem is under-reported. Thirdly, in their discussion they state that 15/25 patients were over the age of 75 and that the median age was 76. I would suggest that the main reason for the cases of pancytopenia may be the increased age of their cohort and/or the multiple other medications they were on concurrently.
We have published our experience in RA patients using MTX from two university centres [3, 4]. From Nashville, among the 248 MTX-treated RA patients followed from 1990 to 2004, no patient developed pancytopenia and only seven cases of a white blood cell (WBC) count below 3.0 x 109/l were seen, with an incidence of 0.7 per 100 person-years. The mean age of this cohort was 55; 34/248 (14%) were older than 75. The New York cohort was reviewed from 1985 to 1999, and only three patients had WBC below 3.0 x 109/l, the lowest being 2.3 x 109/l. Their median age was 59, and 18/182 patients were older than 75 (10%).
MTX is one of the safest disease-modifying antirheumatic drugs, if not the safest. We always need to be vigilant about rare adverse events, but we must also keep in mind the benefits of this therapy and not hinder its use because of adverse events that might possibly have alternative explanations.
The author has declared no conflicts of interest.
References
- Lim AYN, Gaffney K, Scott DGI. Methotrexate-induced pancytopenia: serious and under-reported? Our experience of 25 cases in 5 years. Rheumatology 2005;44:1051–5.
[Abstract/Free Full Text] - Weinblatt ME. Toxicity of low dose methotrexate in rheumatoid arthritis. J Rheumatol 1985;(Suppl. 12):35–9.
- Yazici Y, Sokka T, Kautiainen H, Swearingen C, Kulman I, Pincus T. Long-term safety of methotrexate in routine clinical care: Discontinuation is unusual and rarely due to laboratory abnormalities. Ann Rheum Dis 2005;64:207–11.
[Abstract/Free Full Text] - Yazici Y, Erkan D, Harrison MJ, Nikolov NP, Paget SA. Methotrexate use in rheumatoid arthritis is associated with few clinically significant liver function test abnormalities. Clin Exp Rheumatol 2005;23:517–20.[Medline]
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