Preradiographic axial spondyloarthritis seems to be a rather nonspecific diagnosis because a significant proportion of patients do not progress to ankylosing spondylitis. How can we improve our diagnostic accuracy and distinguish patients with early spondyloarthritis from those with other conditions, such as fibromyalgia?
Filip Van den Bosch: That is a very tricky question. Actually, the question is wrong. I think we should not diagnose nonradiographic axial spondyloarthritis. The diagnosis should actually be spondyloarthritis, full stop, because that is what we do with other diseases. That is what we do with rheumatoid arthritis: we diagnose rheumatoid arthritis, full stop, and then we start describing what we have, whether it is erosive or nonerosive disease, whether it is rheumatoid factor-positive or non-rheumatoid factor-positive disease. I think we should do the same in nonradiographic disease.
The problem that the classification criteria have created is that people started using them as diagnostic criteria, which they were never meant to be. If you are an unexperienced rheumatologist, you create a group where you start ticking boxes and then it is fairly easy – as what you probably are suggesting – to tick a few boxes and say the patient is HLA-B27-positive, has a family member [with the disease], then still one other feature, and then I diagnose – but that is something you should not do. You should first make sure that the whole symptom complex of a patient is fitting the diagnosis of spondyloarthritis, and afterwards it works to say, “well, this is now a patient who is still in the early phase of the disease.” If you do that, my impression is that over the years you will see patients progress. Unless, of course – and that is the final note with regard to this question – it may be that our treatments that we have available right now become better and better and will in the end be able to slow down the progression, so we will not see that horrible form of ankylosing spondyloarthritis, where patients over 10, 20, 30 years grow really stiff.
I think the starting point is that the diagnosis should not be based upon the classification criteria; it should be based on the components that are in there but used by a physician and not by a technician who checks boxes.