First Biologic Drug Persistence in Patients With Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis: A Real-World Canadian Physicians' Experience.

METHODS

Data were obtained from persons enrolled in the SpondyloArthritis Research Consortium of Canada registry between 2003 and 2018. Kaplan-Meier curves were constructed from the time of biologic initiation until discontinuation and compared using the log-rank test. Subanalyses were performed according to calendar year and disease activity. Cox proportional hazards models were used to identify factors associated with discontinuation.

RESULTS

We identified 385 biologic-naive persons. Overall, the 349 AS participants had longer persistence to their first biologic than the 36 nr-axSpA subjects (p < 0.01). The Bath Ankylosing Spondylitis Disease Activity Index and Bath Ankylosing Spondylitis Functional Index decreased by 2.3 points (95% confidence interval [CI], 1.9-2.7) and 3.2 points (95% CI, 2.6-3.7), respectively, in the first year and were stable thereafter. Adjusting for sex, human leukocyte antigen B27, and smoking status, nr-axSpA patients were more likely to discontinue their biologic than AS patients (hazards ratio, 1.65; 95% CI, 1.03-2.62).

CONCLUSIONS

In this real-world study, AS patients had longer persistence to their first biologic compared with nr-axSpA, with disease subtype being the most significant predictor of treatment persistence. Future studies should be targeted at assessing long-term clinical outcome of axSpA in the real-world setting.