To determine the criteria considered important by Dutch rheumatologists in judging whether a patient with ankylosing spondylitis should start tumour necrosis factor (TNF) blocking therapy.
19 Dutch rheumatologists were asked to prioritise various demographic and clinical features for their importance in judging whether a patient should be treated with TNF blocking therapy. In addition, nine Dutch physicians who had referred patients with ankylosing spondylitis for inclusion in an ongoing long term observational study (OASIS) were asked to determine on the basis of case record review for each of their patients whether or not TNF blocking therapy would be considered appropriate.
The variables considered most important were: rate of development of functional impairment; physician's global assessment of current disease activity; physician's global assessment of cumulative disease activity; presence of hip arthritis; physician's global assessment of disease severity. Analysis of the OASIS data (79 patients) showed that patients in whom TNF blocking therapy was considered justified (n = 24; 30%) differed significantly from those in whom it was not considered justified in: patient reported disease activity; functional impairment; spinal mobility; radiographic damage score. Multivariate analysis showed that male sex, function, and radiographic damage were the only independent determinants of a decision to start TNF blocking drugs.
Physicians reported that disease activity, function, and severity were critically important in judging whether to start TNF blocking therapy. In practice, they based their decision more on severity than on activity. They were able to select patients with a high level of radiographic damage, which suggests that this feature captures other domains such as disease activity, spinal mobility, and function.