Spondyloarthropathies

Sizheng Steven Zhao, MBChB (Hons), MRCP, on Smoking and Axial Spondyloarthritis

The impact of smoking on disease severity in axial spondyloarthritis (SpA) has not been thoroughly explained.

In a cross-sectional study, Sizheng Steven Zhao, MBChB(Hons), MRCP, from the Institute of Ageing and Chronic Disease at the University of Liverpool, United Kingdom, and colleagues evaluated the association between smoking and extra-axial manifestations, as well as smoking and disease severity measures, among more than 2000 smokers and former smokers with axial SpA.

Former and current smokers had worse disease than individuals who never smoked, which was indicated by higher Bath Ankylosing Spondylitis Disease Activity Index and Bath Ankylosing Spondylitis Functional Index scores, and increased rates of fatigue, sleep, anxiety, and depression.

Rheumatology Consultant caught up with Dr Zhao about his research.

RHEUMATOLOGY CONSULTANT: What is the overall effect of smoking on axial SpA and ankylosing spondylitis (AS)?

Sizheng Steven Zhao: Smoking is bad for health in general. It increases risk of heart disease, cancer, and rheumatoid arthritis. Studies report that smokers also have a higher risk of developing axial SpA—including AS—and higher rates of spinal damage progression. Our study is one of many showing that smokers with axial SpA report more severe disease and poorer health than nonsmokers. In addition to what is known, we also found that smokers reported worse mood, sleep, fatigue, quality of life, and were more often diagnosed with psoriasis, which is a feature of axial SpA. Since smokers are also more likely to have other lifestyle and health factors that are bad for their axial SpA, it is difficult to untangle the effects of smoking from these other factors. We do not fully know how the poor health associated with smoking would improve if people with axial SpA stopped smoking.

RHEUM CON: Your study found smoking is independently associated with an adverse disease profile in axial SpA. Were you surprised by the findings?

SZ: Smoking had been associated with an adverse disease profile in previous studies. We were the first to show just how many different aspects of poor health were associated with smoking. We were surprised to find that among people with axial SpA, current smokers were less likely to have had uveitis than former smokers and those who never smoked. This goes against what we know about the harms of smoking since smoking is a risk factor for other types of uveitis in the general population. This finding should prompt further research looking at smoking and uveitis in axial SpA.

RHEUM CON: How can a rheumatologist approach treatment for a patient with axial SpA or AS that smokes?

SZ: Almost all patients with rheumatic diseases, including axial SpA, have a higher risk of cardiovascular diseases. Since smoking greatly increases cardiovascular risk, cessation should be universally recommended and promoted, along with other healthy lifestyle changes such as diet and exercise. Other than this, we don’t think smokers should be treated differently for their axial SpA.

RHEUM CON: Would a smoking cessation program be beneficial for this patient population? Is this difficult to implement into practice?

SZ: There are many ways of helping smokers to quit. If cost were not an issue, smoking cessation programs would be a good idea for any patient population. Until we know by how much people’s axial SpA will improve—through high-quality observational studies or randomized controlled trials assessing the causal effects of smoking—we won’t know if such programs will be cost-effective.

RHEUM CON: What are the next steps of your research?

SZ: We are currently studying whether smokers respond differently to axial SpA treatment than nonsmokers. We also hope to examine the unexpected uveitis finding in greater detail. There is also interesting world-class research coming from the British Society for Rheumatology Biologics Register for AS.

Read more about Dr Zhao's study here.

Reference:

Zhao S, Jones GT, Macfarlane GJ, et al. Associations between smoking and extra-axial manifestations and disease severity in axial spondyloarthritis: results from the BSR Biologics Register for Ankylosing Spondylitis (BSRBR-AS). Rheumatology (Oxford). 2019;58(5):811-819. doi:10.1093/rheumatology/key371

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