There is currently no universal consensus on nomenclature for spondyloarthropathy (SpA), or on activity and severity criteria for ankylosing spondylitis (AS).
Points of agreement and majority opinions among 28 international experts in the field were identified by questionnaire. Agreement was defined as >80% concurrence, clear majority as >60% concurrence, and a majority or trend as >50% concurrence.
Respondents agreed on the need for one term that reflects the inflammatory nature of the disease, but no agreement was reached on a specific term. Agreement included subdivision of patients with SpA into AS, psoriatic arthritis, inflammatory bowel disease associated arthritis, and undifferentiated spondyloarthritis/spondyloarthropathy. A majority of experts defined active disease as fulfilling classification criteria for AS and/or a SpA, and disease activity measured by a Bath AS Disease Activity Index (BASDAI) score >4 determined by two patient visits during a two month period, but no maximum radiographic score. The majority of participants considered failure of treatment response to non-steroidal anti-inflammatory drugs (NSAIDs) alone to be a prerequisite for active/severe AS, and 15/28 (54%) thought that NSAID treatment failure should be defined as lack of response to two or more NSAIDs.
Respondents agreed that a two to five year study is the ethical method to demonstrate effects of anti-tumour necrosis factor alpha (TNFalpha) therapy on radiographic progression of AS, and that inclusion criteria should include a certain level of disease activity (measured by BASDAI) and failure of certain treatments. After the efficacy of anti-TNFalpha therapy in AS and psoriatic arthritis is proved, respondents agreed that more studies will be needed to show efficacy for other SpA subsets.