The purpose of this study is to determine the impact of carotid plaque screening on smoking cessation and control of other cardiovascular risk factors.
Tobacco smoking is highly prevalent in Switzerland (31% of adults), and 50% of smokers die from a tobacco-related disease, mainly cardiovascular disease (CVD). The smoking prevalence makes the evaluation of new strategies for smoking cessation a crucial priority. The presence of plaques of atherosclerosis ("cholesterol" deposits in the artery wall), as measured by carotid ultrasound, increases the risk of future CVD. The use of plaque screening to motivate patients to improve smoking cessation has received little attention. In one study, screening for atherosclerotic plaques increased the self-reported rates of smoking cessation, but without biochemical validation of cessation and these smokers had only low nicotine dependence. Moreover, no trial has examined the impact of plaque screening on the control of other cardiovascular risk factors. We now propose a randomized controlled trial of carotid plaque screening in 530 regular smokers aged 40-70 years, recruited from the community, to measure the impact of plaque screening on smoking cessation(main outcome) and control of other cardiovascular risk factors (secondary outcomes) after 1-year follow-up. Secondary outcomes are low-density lipoprotein cholesterol, hemoglobin A1C (if diabetes), high-sensitivity C-reactive protein and blood pressure. Smokers will all receive advice for smoking cessation and, then, will be randomly assigned to either the intervention group (with plaque screening) or the control group (without plaque screening). Smokers with one or more carotid plaque will receive pictures of their own plaques with a standardized explanation. To ensure equal contact conditions, smokers not undergoing ultrasound or without plaque will receive a standardized explanation on the risks of tobacco smoking. This study is innovative because plaque screening is a promising and increasingly used strategy to motivate patients to stop smoking and improve control of cardiovascular risk factors, but its effectiveness has been poorly studied. Successful completion of this project will provide a strong scientific basis for using this strategy for smoking cessation and control of cardiovascular risk factors. If testing is not an effective tool, such testing might represent an important waste of expenditure, and healthcare expenditures should be used for other strategies. Given the scope of the global illness burden due to CVD, the simplicity of the proposed test (ultrasound of carotids) and the smoking prevalence in Switzerland, the evaluation of new strategies for smoking cessation in long-term smokers and the primary prevention of CVD is an important public health priority. Beyond the randomized 1-year study, we have extended the follow-up to 3 years and added abdominal aneurysm screening by ultrasound to the intervention group to assess the association between cardiovascular risk factors and the development of small abdominal aortic aneurysms.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SCREENING
Masking
DOUBLE
Enrollment
536
Carotid ultrasound for plaque screening
We will use the 5A's heuristic (Ask about smoking, Advise on cessation, Assess willingness to change, and for those willing to make quit attempt: Assist with attempt to quit, and Arrange for follow-up) and the gold standard for brief smoking cessation advice. At each visit, smokers will receive smoking cessation counseling and nicotine replacement therapy, similar to the experimental group.
University of Lausanne
Lausanne, Switzerland
Smoking abstinence: one-week point prevalence abstinence, ascertained by self-report and confirmed by exhaled carbon monoxide (CO) and by the level of serum cotinine
Time frame: 1 year, 3 years
Continuous smoking abstinence from quit date and one-week point prevalence abstinence, ascertained by self-report and confirmed by exhaled carbon monoxide (CO)
Time frame: 8 weeks, 26 weeks, 1 year, 3 years
Change in control of other cardiovascular risk factors: low-density lipoprotein cholesterol, hemoglobin A1C (if diabetes), high-sensitivity C-reactive protein (hs-CRP) and blood pressure.
Time frame: 1 year, 3 years
Change in overall cardiovascular risk, as measured by the Framingham risk score
Time frame: 1 year, 3 years
Change in drug adherence, as measured by adherence questionnaire
Time frame: 1 year, 3 years
Change in quality of life, as measured by SF-36
Time frame: 1 year, 3 years
Change in physical activity, as measured by International Physical Activity Questionnaire questionnaire (IPAQ)
Time frame: 1 year, 3 years
Increase in harms potentially associated with screening: stress and depression, as measured depression scores with the Beck Depression Inventory and the 4-item Perceived Stress Scale
Time frame: 1 year, 3 years
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