Confronting smokers with previously undetected airflow limitation for smoking cessation

PhD thesis, Maastricht University Press, 2008 (ISBN: 978 90 5278 781 7)

Kotz D

Summary

Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease which is characterized by airflow limitation that is not fully reversible. It is the fifth leading cause of death worldwide, and projections for 2020 indicate a further increase in global mortality, eventually placing COPD in third position of lethal diseases. Cigarette smoking is by far the most important risk factor for COPD; at least 15% to 50% of smokers are estimated to develop COPD during their lifetime. Smoking cessation is the single most effective way to reduce the risk of developing COPD and to affect the outcome in patients at all stages of the disease.

Despite the well-known health risks of smoking, many people still smoke (in the Netherlands currently about 29%). Whereas most smokers do want to quit, only a fraction of those who try remain long-term abstinent, mainly because of nicotine and tobacco dependence. The two main types of treatment that can help addicted smokers to quit are pharmacological and behavioural treatment. But even when treated with a combination of both, about 75% or more of smokers making an attempt to quit relapse within the first year and resume smoking.

It is important to improve smoking cessation strategies, especially in smokers with COPD, who have a greater and more urgent need to stop smoking than the average smoker. A potentially successful motivational tool may be spirometry, which is the gold standard for the diagnosis and assessment of COPD. Confronting smokers with an objectively identified negative consequence of smoking by spirometry (airflow limitation, COPD) may possibly improve the outcome of their attempt to quit. Various studies have been performed to study the efficacy of spirometry for smoking cessation but the results are inconclusive.

The main part of this thesis is a randomized controlled trial on the efficacy of COnfronting SMOkers with spirometry for smoking cessation; the COSMO trial. We hypothesised that early detection of COPD and confrontation with spirometry for smoking cessation may be effective if certain conditions are met which we describe in chapter 4; confronting patients with COPD should not be an isolated approach but should be integrated into state-of-the-art smoking cessation treatment consisting of several counselling sessions on an individual, face-to-face level, under supervision of a trained smoking cessation specialist, and in combination with evidence-based pharmacotherapy for smoking cessation. We termed this approach “confrontational counselling”, and tested its efficacy in a randomized controlled trial. The protocol of the COSMO trial is presented in chapter 5.

All smokers from the COSMO trial had previously undetected airflow limitation. It has been suggested that early detection of smokers with COPD may be enhanced by using questionnaires to identify patients with a high likelihood of having airflow limitation before using spirometry. GPs may use a COPD diagnostic questionnaire such as the one that is recommended by the International Primary Care Airways Group. Before this new diagnostic questionnaire can be accepted and applied reliably in clinical practice, the analysis of the underlying model must be repeated on new data collected from an appropriate sample of subjects from a different setting. We performed this external validation in 676 smokers that we screened for eligibility for participation in the COSMO trial (chapter 6). The ability of the COPD diagnostic questionnaire to discriminate between subjects with and without COPD was poor: the area under the receiver operating characteristics curve (ROCAUC) was 0.65 (the ROCAUC can take values from 0.5 (totally uninformative) to 1.0 (totally informative diagnostic test)). We concluded that this questionnaire is probably not useful as a diagnostic tool to identify patients with an increased risk of airflow limitation in a population of current heavy smokers.

The primary research question of the COSMO trial was whether confrontational counselling increased long-term abstinence rates from smoking during a period of 52 weeks after the target quit date (chapter 7). A total of 296 smokers with previously undetected mild to moderate airflow limitation were randomly allocated to; medium intensity confrontational counselling delivered by a respiratory nurse combined with nortriptyline for smoking cessation (experimental group), medium intensity health education and promotion delivered by a respiratory nurse combined with nortriptyline for smoking cessation (control group 1), or “care as usual” for smoking cessation by the general practitioner (control group 2). Only smokers from the experimental group were confronted with their abnormal lung function. The results showed no difference in cotinine validated prolonged abstinence rate between the experimental group and control group 1 from week 5 through 52 (odds ratio (OR) = 0.96, 95% confidence interval (CI) = 0.43, 2.18). The high failure rates (88% and higher) highlight the need for treating tobacco addiction as a chronic relapsing disorder, especially in smokers with respiratory disease, who have a more urgent need to stop.

We were not only interested whether or not confrontational counselling was effective but also how it might work. When we designed the intervention, we hypothesised that confrontational counselling – through labelling with a potentially life-threatening illness status – increases risk perception and health concerns and decreases self-exempting beliefs in smokers, changes which in turn may account for abstinence from smoking. To analyse these mechanisms of change, we performed a mediation analysis on the effects of confrontational counselling on short-term abstinence from smoking in the 288 smokers from the experimental group and control group 1 of the COSMO trial (chapter 8). Cotinine validated abstinence rates from smoking at 5 weeks after the target quit date were 43.1% in the experimental group versus 31.3% in control group 1 (OR=1.67, 95%CI=0.97, 2.87). The effect of confrontational counselling on abstinence was independently mediated by the expectation of getting a serious smoking related disease in the future (OR=1.76, 95%CI=1.03, 3.00), self-exempting beliefs (OR=0.42, 95%CI=0.21, 0.84), and self-efficacy (OR=1.38, 95%CI=1.11, 1.73).

Irrespectively of its efficacy, it is worth considering whether an approach of early detection and labelling with COPD is justifiable. Labelling with disease – confronting subjects with a previously undetected or unrecognized disease status – has long been an issue of debate in the medical field. In most cases, the debate has focused on the potential adverse effects of labelling, but it is also possible that it has positive effects (e.g. labelling with COPD may motivate smokers to quit smoking). We conducted semi-structured ethical exit interviews on this subject in 205 participants from the COSMO trial  to assess their opinions on the effectiveness of spirometry for smoking cessation, the justification of early detection of airflow limitation in smokers, and the impact of confrontation with COPD (chapter 9). Our results showed that labelling with disease is probably a less important issue in the discussion about the pros and cons of early detection of COPD; the majority of participants (86%) agreed that it is justified to measure lung function in heavy smokers. These participants argued that measuring lung function raises consciousness about the negative effects of smoking, helps to prevent disease, or increases motivation to stop smoking. Most of the participants who disagreed argued that routinely measuring lung function in smokers would interfere with one’s freedom of choice.

Apart from the COSMO trial, we conducted observational research on smoking cessation practices of Dutch health care providers. According to national and international guidelines on the treatment of tobacco dependence, health care providers such as GPs, cardiologists, lung physicians, and respiratory nurses can play an important role in reducing the prevalence of smoking. However, it is unclear what their smoking cessation practices, attitudes, and perceived effectiveness are. To answer these questions, we conducted national surveys among 834 GPs, 300 cardiologists, 258 lung physicians (these three surveys are combined in chapter 2), and 254 respiratory nurses (chapter 3). Results from theses surveys showed that the prevalence of current smoking among Dutch physicians and respiratory nurses has decreased sharply in recent years and is low (4-8%) compared with the general population (about 29%). Of the pharmacological aids for smoking cessation, physicians recommended bupropion most frequently to their patients, followed by nicotine patches and nicotine gum. Furthermore, more lung physicians than GPs and cardiologists recommended the use of bupropion, nicotine patch, and nicotine gum. The respiratory nurses reported to be compliant with the Dutch protocol for the treatment of nicotine and tobacco addiction (the so-called “L-MIS”); seven out of ten behavioural techniques for smoking cessation from the protocol were used by more than 94% of the respondents. Perceived lack of patient’s motivation formed the most important threat to respiratory nurses’ future smoking cessation activities. International guidelines acknowledge that respiratory patients have a more urgent need to stop smoking but have more difficulty doing so. They should be offered the most intensive smoking cessation counselling in combination with pharmacotherapy. Behavioural counselling for smoking cessation may be more feasible for respiratory nurses than for physicians who often lack time.

As stated before, a considerable proportion of the population smokes despite the well-known health risks of smoking. Furthermore, there is a large socio-economic gradient in smoking in the Netherlands as in other developed countries with the highest prevalence of smoking in half-skilled and unskilled manual labour (44% in the Netherlands in 2007) and the lowest prevalence in highly-skilled white-collar workers (27%). This gradient is estimated to be responsible for half of socioeconomic differences in mortality in men aged 35-69 years in developed countries. An important future goal is to reduce social health inequalities that are caused by smoking. Reducing inequalities in smoking prevalence requires a better understanding of what is causing it. We used data from 6,950 respondents to a UK cross-sectional household survey to examine the variation across social grades in: rates of attempts to stop smoking; use of pharmacological and behavioural treatment for smoking cessation; and success rates of quit attempts (chapter 10). A total of 2,983 respondents had tried to stop in the past year and 469 reported having stopped at the time of the survey. The results showed no difference across social grades in the rate of attempts to stop (42.7% in the highest social grade AB to 41.3% in the lowest social grade E), use of medications to aid cessation (46.7% of those making quit attempts in AB to 50.9% in E) or use of National Health Service Stop Smoking Services (7.0% of those making quit attempts in AB to 4.8% in E). There was, however, a large difference in success rates: 20.4% in social grade AB versus 11.4% in social grade E of those who made attempts were still not smoking by the time of the survey.

Statements accessory to the PhD thesis

  1. In smokers who are interested in quitting, confrontation with abnormal results from spirometry does not increase long-term smoking cessation rates. (this thesis)
  2. 2. A counselling approach in which smokers are confronted with evidence of airflow limitation can decrease smokers’ self-exempting beliefs (i.e. denial of being at risk of a smoking-related disease) and may subsequently increase short-term smoking cessation rates. (this thesis)
  3. The sample for the development of a symptom-based diagnostic tool for early detection of chronic obstructive pulmonary disease (COPD) should be stratified by smoking status. (this thesis)
  4. The social gradient in smoking prevalence cannot be explained by variation in the rates of attempts to quit but rather by a lower likelihood of success of these attempts in smokers from lower social grades. (this thesis)
  5. Perceived lack of patients’ motivation to quit smoking is the most important barrier to health care professionals’ smoking cessation activities.
  6. The transtheoretical (stages-of-change) model should be put to rest. (West, Addiction 2005; 100 (8): 1036-1039)
  7. Scientific researchers should report a unique researcher identification number on all their scientific output. (Cals & Kotz, Lancet 2008; 371 (9631): 2152-2153)
  8. The copy/paste function of word processing programmes is a threat to science.
    The copy/paste function of word processing programmes is a threat to science.
    The copy/paste function of word processing programmes is a threat to science.
  9. Many Europeans have a negative attitude towards the European Union because they take its many positive accomplishments for granted (such as everybody’s right to travel, work and live throughout the union).
  10. Germans who are nice and funny are often perceived as “not typically German” by Dutch people.
  11. Music is the only language that can be spoken directly from heart to heart.
Advertisements

About this entry