Background
Tobacco smoking increases the risk of developing inflammatory joint diseases (IJDs) such as rheumatoid arthritis, where the joints are progressively damaged by the body's own immune system. Smoking may also worsen symptoms of these diseases. This review looked at whether supportive programmes to help smokers with IJDs quit smoking actually lead to quitting and reduced inflammation in the joints and elsewhere. Inflammation from these diseases can lead to heart attack and stroke, for which people with IJD are at higher risk.
Study characteristics
We searched the literature in October 2018. We included two studies with a total of 57 adult smokers - both men and women - with rheumatoid arthritis. One of the studies tested an intervention to help people with rheumatoid arthritis to quit smoking. This study recruited only smokers and compared this specialist, stop smoking programme with a standard, less intensive stop smoking programme. The other study tested an intervention to reduce the risk of heart disease and stroke in people with rheumatoid arthritis. Researchers recruited non-smokers and smokers and compared this programme to a brief factual information leaflet about risks of heart disease. Both studies followed study participants for six months.
These studies were funded by Arthritis Research UK Educational Research Fellowship, Arthritis Research UK, the New Zealand Health Research Council, Arthritis New Zealand, and the University of Otago Research Fund.
Key results
Neither of the two included studies found that the more intensive, specialist interventions aimed at people with rheumatoid arthritis helped more people with rheumatoid arthritis to quit smoking than the less intensive, generic interventions. Only one of the studies reported on the safety of the stop smoking programme used. Very few side effects related to use of nicotine replacement therapy were reported, and none of these were serious. As a result, we do not know whether helping people with inflammatory arthritis improves their disease.
Quality of the evidence
We rated the overall quality of the included studies as very low because studies were very few and included few participants; only one of the studies tested an intervention that specifically tried to help people to quit smoking, and there is a chance that people who received the intensive intervention were more likely to incorrectly report that they had stopped smoking when in fact they had not. As a result, further large studies should be carried out to test stop smoking programmes for people with IJD. Researchers should ensure that they measure whether people's IJD symptoms improve, and should confirm whether people have stopped smoking.
We found very little research investigating the efficacy of smoking cessation intervention specifically in people with IJD. Included studies are limited by imprecision, risk of bias, and indirectness. Neither of the included studies investigated whether smoking cessation intervention reduced disease activity among people with IJD. High-quality, adequately powered studies are warranted. In particular, researchers should ensure that they measure disease markers and quality of life, in addition to long-term smoking cessation.
Chronic inflammatory joint diseases (IJDs) affect 1% to 2% of the population in developed countries. IJDs include rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA), and other forms of spondyloarthritis (SpA). Tobacco smoking is considered a significant environmental risk factor for developing IJDs. There are indications that smoking exacerbates the symptoms and worsens disease outcomes.
The objective of this review was to investigate the evidence for effects of smoking cessation interventions on smoking cessation and disease activity in smokers with IJD.
We searched the Cochrane Tobacco Addiction Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library; PubMed/MEDLINE; Embase; PsycINFO; the Cumulative Index to Nursing and Allied Health Literature (CINAHL); and three trials registers to October 2018.
We included randomised controlled trials testing any form of smoking cessation intervention for adult daily smokers with a diagnosis of IJD, and measuring smoking cessation at least six months after baseline.
We used standard methodological procedures as expected by Cochrane.
We included two studies with 57 smokers with a diagnosis of rheumatoid arthritis (RA). We identified no studies including other IJDs. One pilot study compared a smoking cessation intervention specifically for people with RA with a less intensive, generic smoking cessation intervention. People included in the study had a mean age of 56.5 years and a disease duration of 7.7 years (mean). The second study tested effects of an eight-week cognitive-behavioural patient education intervention on cardiovascular disease (CVD) risk for people with RA and compared this with information on CVD risk only. The intervention encouraged participants to address multiple behaviours impacting CVD risk, including smoking cessation, but did not target smoking cessation alone. People included in the study had a mean age of 62.2 years (intervention group) and 60.8 years (control group), and disease duration of 11.6 years (intervention group) and 14.1 years (control group). It was not appropriate to perform a meta-analysis of abstinence data from the two studies due to clinical heterogeneity between interventions. Neither of the studies individually provided evidence to show benefit of the interventions tested. Only one study reported on adverse effects. These effects were non-serious, and numbers were comparable between trial arms. Neither of the studies assessed or reported disease activity or any of the predefined secondary outcomes. We assessed the overall certainty of evidence as very low due to indirectness, imprecision, and high risk of detection bias based on GRADE.