Rheumatology Advance Access originally published online on July 4, 2006
Rheumatology 2006 45(9):1176-1177; doi:10.1093/rheumatology/kel181
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BSR guidelines for TNF blockers in ankylosing spondylitis—how useful are they?
Deptartment of Rheumatology, Connolly Hospital, Blanchardstown, Dublin 15, Ireland
Correspondence to: Dr M. Barry. E-mail: mbarry{at}ireland.com
SIR, We are writing in response to the British Society of Rheumatology (BSR) guidelines for prescribing tumour necrosis factor (TNF) blockers in adults with ankylosing spondylitis (AS) [1]. There are several points that we would like to make.
The first issue relates to the ongoing reliance on the modified New York criteria [2] for the diagnosis of AS and eligibility for treatment. They have largely been the criteria employed in trials of anti-TNF therapy in AS to date, but appear increasingly outdated. The attitude to this disease has greatly changed with the role of imaging modalities such as magnetic resonance imaging in early diagnosis and recognition of the potential for early treatment. Recently published data [3] show that a shorter disease duration is one of the main predictors of a major clinical Bath Ankylosing Spondylitis Disease Activity Index (BASDAI 50) response to anti-TNF.
Looking at the clinical part of the criteria, relevance and applicability must be put in question, as they call for subjective assessments of ‘limited’ range of motion of lumbar spine and chest expansion compared to ‘normal’ values for sex and age. We have not encountered these values in everyday practice. When first drawn up, they were evaluated in people with established disease and may perform well in this group, but studies have shown that they are not sensitive when applied to those with shorter symptom duration [4, 5]. It has also been shown that the specificity of ‘restriction of spinal mobility’ can vary as much as 37–75%.
Using the modified New York criteria, the radiological criterion of grade 2 sacroiliitis bilaterally or grades 3 or 4 unilaterally infers ongoing disease, on average, of 9 yrs, according to one series [6]. Surely a set of guidelines that aims to be relevant to clinical practice should be recommending treatment before they reach such an advanced stage; these criteria are not sensitive enough in diagnosis of ‘pre-radiographic’ AS. There is also the issue of the specificity of diagnosing radiographic sacroiliitis, especially differentiating between grade 1 and 2, which constitutes the difference between ‘no disease’ and ‘disease’.
There is no stipulation in the guidelines as to the use of MRI for early diagnosis instead of applying the New York criteria.
Perhaps, the working group, when they review the guidelines next year, should consider an alternative set of criteria for diagnosis, such as the one proposed by Rudwaleit et al. [7]. They propose a model for early diagnosis of axial spondyloarthopathy, in patients with inflammatory back pain but normal X-rays, using clinical features, laboratory findings and skeletal imaging.
Regarding the criteria for withdrawal of therapy, the recommendation laid down is to withdraw treatment if proven to be ‘ineffective’ after 3 months as judged by lack of reduction in scores such as the BASDAI and visual analogue scores (VSA). There is no firm recommendation for using an alternative biological agent or shortening the interval between treatment if using infliximab. A recent study from Spain [8] showed that there may be benefit to patients with persistent disease in reducing the dosage interval from 8 to 6 weeks for those on infliximab 5 mg/kg.
Finally, with regard to periodic review of the need for continued treatment and possible dose reduction, the guidelines are not very clear. This really reflects the lack of adequate evidence on this issue. Baraliakos et al. [9] have, however, recently published data on a group of patients with established AS who had received 3 yrs of continuous infliximab treatment, which was then stopped to see if remission was sustainable. Of 42 patients, 41 were restarted on therapy within a year because of relapse.
C.S. has received a research grant from Wyeth Pharmaceuticals. The other authors have declared no conflicts of interest.
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- Keat A and Barkham N, et al. (2005) BSR guidelines for prescribing TNF-
blockers in adults with ankylosing spondylitis. Report of a working party of the British Society for Rheumatology. Rheumatology 44:439–47. - Van der Linden S, Valkenburg HA, Cats A. (2005) Evaluation of diagnostic criteria for ankylosing spondylitis: a proposal for modification of the New York criteria. Arthritis Rheumatology 44:939–47.
- Rudwaleit M, Listing J, Brandt J, et al. (2004) Prediction of a major clinical response (BASDAI 50) to tumour necrosis factor blockers in ankylosing spondylitis. Ann Rheum Dis 63:665–70.
[Abstract/Free Full Text] - Goei The HS, Steven MM, van der Linden SM, Cats A. (1985) Evaluation of diagnostic criteria for ankylosing spondylitis: a comparison of the Rome, New York and modified New York criteria in patients with a positive screening test for ankylosing spondylitis. Br J Rheumatol 24:242–9.
[Abstract/Free Full Text] - Rudwaleit M, Listing J, Marker-Hermann E, et al. (2004) Spinal mobility in early ankylosing spondylitis and in axial SpA without definite radiographic sacroiliitis. Ann Rheum Dis 63:Suppl 1, 400.
- Mau W, Zeidler H, Mau R, et al. (1988) Clinical features and prognosis of patients with possible ankylosing spondylitis. Results of a ten-year follow up. J Rheumatol 15:1109–14.[Web of Science][Medline]
- Rudwaleit M, van der Heijde D, Khan MA, et al. (2004) How to diagnose axial spondyloarthropathy early. Ann Rheum Dis 63:535–43.
[Abstract/Free Full Text] - Collantes-Estevez E, Munoz-Villanueva MC, Zarco P, et al. (2005) Effectiveness of reducing infliximab dose interval in non-responder patients with refractory spondyloarthropathies. An open extension of a multicentre study. Rheumatology 44:1555–8.
[Abstract/Free Full Text] - Baraliakos X, Listing J, Brandt J, et al. (2005) Clinical response to discontinuation of anti-TNF therapy in patients with ankylosing spondylitis after 3 years of continuous treatment with infliximab. Arthritis Res Ther 7:R439–44.[CrossRef][Web of Science][Medline]
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