Smoking status and cause-specific discontinuation of tumour necrosis factor inhibitors in axial spondyloarthritis

The impact of smoking status on radiographic progression in patients with ankylosing spondylitis on anti-tumor necrosis factor treatment

Background

Ankylosing spondylitis (AS) is characterized by back pain which can lead to spinal ankylosis. Anti-tumor necrosis factor (TNF) dramatically alleviates symptoms, but spinal damage can still be progressive even during anti-TNF treatment. Smoking is a one of well-known risk factors for structural damage in AS. However, it has not been confirmed that smoking can affect radiographic progression even during anti-TNF treatment.

Objective

To investigate factors associated with radiographic progression during anti-TNF treatment with a focus on smoking status which is known as one of poor prognostic factors for AS.

Materials and methods

We conducted a retrospective cohort study of AS patients who began the first-line anti-TNF treatment between 2001 and 2018 according to availability of smoking data. All enrolled patients were observed until the last visit, the first-line anti-TNF discontinuation, or December 2019. Radiographic damage was assessed using the modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS). The mSASSS progression rate (units/year) was calculated using the baseline mSASSS, the final mSASSS during observation period, and the duration between them. Univariable and multivariable logistic regression analyses were performed to identify associated factors of mSASSS progression rate > 1 unit/year.

Results

Among 459 AS patients, 185 (40.3%) patients were never smokers, 62 (13.5%) were ex-smokers and 212 (46.2%) were current smokers at baseline. Ex- and current smokers had higher mSASSS progression rates than never smokers [never smoker 0.1 (0.0–0.7), ex-smoker 0.6 (0.0–1.5), and current smoker 0.6 (0.0–1.5) units/year, P < 0.001]. In the multivariable logistic analysis, current smoking [adjusted odds ratio (OR) 1.69, 95% CI 1.01–2.82, P = 0.047] and higher baseline mSASSS [adjusted OR 1.03, 95% CI 1.01–1.04, P < 0.001] were associated with a mSASSS progression rate > 1 unit/year.

Conclusion

Current smoking is a modifiable risk factor for radiographic progression in patients with AS on anti-TNF treatment. Quitting smoking should be strongly recommended.

Factors affecting drug survival of an alternative TNF inhibitor and secukinumab in patients with ankylosing spondylitis switching from the first TNF inhibitor

BACKGROUND

To investigate factors associated with drug survival of an alternative tumour necrosis factor inhibitor (TNFi) and secukinumab (SEC) after switching from the first TNFi in patients with ankylosing spondylitis (AS).

METHODS

We included a total of 78 patients with AS who switched to an alternative TNFi (n = 56) or SEC (n = 22) from the first TNFi. Patient characteristics at the time of switching and drug discontinuation rate were compared between the two groups. Cox regression analyses were performed to evaluate factors associated with the risk of discontinuing the alternative TNFi and SEC.

RESULTS

The proportion of patients with syndesmophytes was numerically lower (28.6% versus 45.5%, p = 0.155) and the C-reactive protein (CRP) level was numerically higher [3.8 (1.0-15.4) mg/L versus 1.1 (0.5-3.5) mg/L, p = 0.060] in patients who received an alternative TNFi. The drug discontinuation rate (alternative TNFi: 35.7% versus SEC: 36.4%, p = 0.957) and reasons for discontinuation were similar (primary failure, p = 0.342; secondary failure, p > 0.999; and adverse events, p = 0.670) between the two groups. A higher CRP level at switching was associated with a lower risk (adjusted HR = 0.93, 95% CI = 0.87-0.99, p = 0.022) of discontinuing the alternative TNFi, and primary failure of the first TNFi was associated with a higher risk [adjusted HR (HR) = 5.20, 95% confidence interval (CI) = 1.91-14.11, p = 0.001]. Current smokers (adjusted HR = 5.77, 95% CI = 1.20-27.74, p = 0.029) and the presence of syndesmophytes (adjusted HR = 7.49, 95% CI = 1.39-40.23, p = 0.019) were associated with a higher risk of discontinuing SEC.

CONCLUSION

When switching the drug from the first TNFi in patients with AS, an alternative TNFi could be preferable in patients with higher CRP levels or syndesmophytes, or current smokers, whereas SEC could be a better choice in patients who presented primary failure of the first TNFi in terms of drug survival.

Smoking in spondyloarthritis: unravelling the complexities

Tobacco smoking is a major threat to health. There is no doubt about the need to promote and support cessation at every opportunity. Smoking has a clear role in RA, but what evidence is there that the same relationship exists in SpA? In this review, we examine (the less cited) paradoxes and contradictions in the existing axial SpA (axSpA) and PsA literature; for example, smoking appears to be 'protective' for some axSpA manifestations. We also highlight findings from higher quality evidence: smoking is associated with increased risk of PsA and the risk of psoriasis in axSpA. The relationship between smoking and SpA is far from simple. Our aim is to highlight the harms of smoking in SpA and bring attention to inconsistencies in the literature to inform further research.

Influence of smoking and obesity on treatment response in patients with axial spondyloarthritis: a systematic literature review

To assess whether smoking and obesity are predictors of poor treatment response in patients with axial spondyloarthritis (axSpA). A systematic literature review was performed by searching in MEDLINE and EMBASE up to June 2019 with a strategy based on the PICO approach: Population: patients with axSpA; Intervention or exposure: smoking or obesity; Comparison: non-smokers (for smoking) and normal-weight individuals (for obesity); and Outcome: any response criteria currently validated for axSpA. The 2009 Oxford Centre for Evidence-based Medicine levels were used for assessing the studies quality. Out of 1873 references retrieved, 46 studies were selected for full-text review and 12 for data extraction: six stratified patients by smoking and six by obesity. All were longitudinal observational studies, except one, which was cross-sectional. Overall, these studies included 5291 patients (3917 for smoking and 1333 for obesity), and all these patients were on anti-tumor necrosis factor (anti-TNF) therapy. The quality of evidence was graded as level 2b except that from the cross-sectional study which was graded level 4. For smoking, the evidence found is inconsistent: two studies finding negative effects in response to anti-TNF while the other four found no differences in clinical response to this therapy. Regarding obesity, the evidence is more consistent: five of the six studies describing a negative influence in response to anti-TNF. According to the scientific evidence in patients with axSpA, obesity is associated with a more unsatisfactory response to anti-TNF therapy. A poorer response in smokers has yet to be demonstrated. Key Points • Identifying predictors of treatment response in axSpA, especially those that are modifiable, is relevant. • Obesity increases the risk of poorer response to anti-TNF agents in patients with axSpA. • Scientific evidence for smoking habit as a predictor of treatment response in axSpA is inconclusive.

Biomarker development for axial spondyloarthritis

The term axial spondyloarthritis (axSpA) encompasses a heterogeneous group of diseases that have variable presentations, extra-articular manifestations and clinical outcomes, and that will respond differently to treatments. The prototypical type of axSpA, ankylosing spondylitis, is thought to be caused by interaction between the genetically primed host immune system and gut microbiota. Currently used biomarkers such as HLA-B27 status, C-reactive protein and erythrocyte sedimentation rate have, at best, moderate diagnostic and predictive value. Improved biomarkers are needed for axSpA to assist with early diagnosis and to better predict treatment responses and long-term outcomes. Advances in a range of 'omics' technologies and statistical approaches, including genomics approaches (such as polygenic risk scores), microbiome profiling and, potentially, transcriptomic, proteomic and metabolomic profiling, are making it possible for more informative biomarker sets to be developed for use in such clinical applications. Future developments in this field will probably involve combinations of biomarkers that require novel statistical approaches to analyse and to produce easy to interpret metrics for clinical application. Large publicly available datasets from well-characterized case-cohort studies that use extensive biological sampling, particularly focusing on early disease and responses to medications, are required to establish successful biomarker discovery and validation programmes.