According to longitudinal study results published in Arthritis Research & Therapy, smoking status did not affect the discontinuation of tumor necrosis factor inhibitors (TNFis) in patients with axial spondyloarthritis (axSpA).
Investigators abstracted data from the British Society for Rheumatology Biologics Register for Ankylosing Spondylitis (BSRBR-AS) that included a prospective cohort study of patients with axSpA in the United Kingdom. Patients fulfilling the Assessment of SpondyloArthritis international Society (ASAS) criteria for axSpA, who started their first TNFi from 2012 to 2017, were eligible for inclusion. As per BSRBR-AS protocol, patients underwent clinical assessments at baseline and at 3, 6, and 12 months after TNFi initiation, with follow-ups continuing annually after the 12-month point. Smoking status was ascertained by self-report; TNFi discontinuation was determined from medical notes. Cox proportional hazard models were used to estimate hazard ratios (HRs) for TNFi discontinuation according to smoking status.
A total of 758 patients provided 954 patient-years of follow-up. Mean patient age was 45 years; the majority of patients (66%) were men; 34% were current smokers, 30% ex-smokers, and 36% never-smokers. TNFi was discontinued in 174 (23%) patients; median time to discontinuation was 6 months. Among patients who discontinued TNFi, 26% stopped because of infections, 20% because of other adverse events, and 44% because of inefficacy or other reasons. Compared with never-smokers, HRs for all-cause TNFi discontinuation did not significantly differ in current smokers (HR, 0.79; 95% CI, 0.53-1.20) or ex-smokers (HR, 0.68; 95% CI, 0.45-1.04).
Among current smokers, no increased rates of discontinuation were observed as a result of infections (HR, 0.79; 95% CI, 0.40-1.54), other adverse events (HR, 0.86; 95% CI, 0.41-1.78), or inefficacy/other reasons (HR, 1.44; 95% CI, 0.86-2.41). In conclusion, smoking status affected neither overall nor cause-specific TNFi discontinuation rates.
Baseline smoking status did not affect TNFi discontinuation rates in this cohort of UK patients with axSpA. Further research is necessary to confirm these findings and explore more specific causes of TNFi discontinuation in patients with axSpA.
Zhao SS, Yoshida K, Jones GT, et al. Smoking status and cause-specific discontinuation of tumour necrosis factor inhibitors in axial spondyloarthritis. Arthritis Res Ther. 2019;21:177.