Is there a role for sulphasalazine in axial spondyloarthritis in the era of TNF inhibition? Data from the NOR-DMARD longitudinal observational study.

Objectives: The objectives of this study were to characterize patients with predominantly axial SpA who received SSZ as their first DMARD, compare the response to treatment in patients with and without peripheral disease and identify predictors of discontinuation of SSZ. We also investigated response to TNF inhibitor (TNFi) after SSZ failure.

Methods: We included DMARD-naive patients with predominantly axial SpA starting SSZ or TNFi treatment from a Norwegian, multicentre longitudinal observational study (NOR-DMARD). In patients starting SSZ, we compared the 3-month responses between patients with and without swollen joints and identified predictors of discontinuation by Cox regression analysis. Sixty-six SSZ-treated patients later switched to a TNFi, and we compared their 3-month responses and drug survival to patients starting a TNFi as their first DMARD.

Results: Patients receiving SSZ (n = 181) as their first DMARD had shorter disease duration, were more frequently female and had more swollen joints than those starting TNFi (n = 543). There was a trend toward better 3-month responses to SSZ in patients with peripheral joint swelling, and they had significantly better 3-year drug survival than patients without swollen joints at baseline. Predictors of SSZ discontinuation were no peripheral joint swelling, higher CRP and higher BASDAI back pain score. TNFi response was similar in patients previously treated with SSZ, as in DMARD-naive patients.

Conclusion: Our findings support current recommendations of SSZ as an optional treatment in SpA patients with peripheral disease, although overall responses were modest. Initial treatment with SSZ does not seem to impair later TNFi response.