Diagnosis of AS according to 1984 modified New York criteria |
Persistent disease activity for at least 4 months (BASDAI?) |
Stage of disease (degree of ankylosis) |
Insufficient conventional therapy (definition needed) |
Failure of at least three NSAIDs (including phenylbutazone?) at maximal dose to constantly suppress disease activity |
Failure of NSAIDs treatment is not necessary if NSAIDs are not tolerated or renal insufficiency is present |
Failure of DMARD therapy (3 g sulfasalazine daily for 4 months) |
Failure of intra-articular corticosteroid therapy (at least 2 injections?) |
Failure of low-dose prednisolone (<10 mg daily for 1 week?) |