“Effect on Smoking quit rate of telling patients their lung age: the step 2 quit randomised controlled trial”
Article Review by : Pooja Singhal, MD
Structure
Background
* Currently 23% Men and 19% women in USA smoke
* Cigarette smoking was estimated to be responsible for nearly 5 million premature deaths worldwide in 2000
* In the United States (US), cigarette smoking is the major preventable cause of disease, and is estimated to result in more than 400,000 deaths annually.
* The most important causes of smoking-related mortality include atherosclerotic cardiovascular disease, lung cancer, and chronic obstructive pulmonary disease (COPD)
* The incidence of a MI has increased six-fold in women and threefold in men who smoke at least 20 cigarettes per day compared to subjects who never smoked
* In the United States alone, the health consequences and productivity losses associated with smoking are estimated to cost in excess of 90 billion dollars every year
Smoking Cessation- Role of a Physician
* 70% smokers see a physician each year
* Advice from physician leads to a spontaneous quit rate of 2-4%
* Pharmacological vs. Behavorial Approach
* Pharmacological- Bupropion, Nicotine replacement therapy, and varenicline
* Behavorial – counseling and motivational interviewing
* Pt.s willing to quit -5 A’s – Ask, Assess, Advise, Assist and Arrange
* Pts unwilling to quit- 5 R’s- Relevance, Rewards, Roadblocks, and Repetition
Whether the biomarkers like Cotinine or tests like Spirometry can promote Smoking cessation?
Research so far – Role of Biomarkers in Smoking cessation?
Research Study
* Hypothesis- Telling smokers their “lung age” would lead to successful smoking cessation, especially in those with most damage.
* Design- Randomized controlled trial
* Setting- 5 general practices in Hertfordshire, England
* Participants- 561 current smokers aged over 35, control 281, intervention 280
Exclusion Criteria:
* Patients on home Oxygen
* Hx of lung cancer
* Silicosis
* TB
* Asbestosis
* Pneumonectomy
Table 2 Baseline characteristics of groups. Figures are means (SDs) unless stated otherwise
Instruments used to confirm baseline comparability of groups
* St. George’s respiratory questionnaire- self administered under supervision and to measure the impact of respiratory diseases (asthma and COPD) on an individual’s life.
* Prochaska’s stages of change questions in relation to smoking
Instruments and Test
* MicroLab 3500 Spirometers- newly purchased
* Saliva samples for Cotinine testing with documentation of people on nicotine replacement therapy
Men Lung age=2.87 x height (in inches)–(31.25 x observed FEV1 (litres)–39.375
Women Lung age=3.56 x height (in inches)–(40 x observed FEV1 (litres)–77.28
Lung age calculation formula developed
by Morris and Temple5
Lung Age - The age of the average healthy individual who would perform similar to them on spirometry.
Intervention vs. control group
* If the lung age was equal to or less than the individual’s chronological age, he or she was informed test result was normal
* Lung age> chronological age – lung age in years given
* Control group – no results given – told them they would be reinvited for a second test after 12 months to see if there had been any change in lung fxn
* 4 weeks – After reviewing the results with checking quality of the spirometry tracing, written results were sent to both control and intervention group
* Control group – FEV1 with no further explanation
* Intervention group – Lung age
Communication to the patients (Intervention group)
* Results after Spirometry given immediately in the form of lung age
* Visual aid (graphs)
* Verbal Counseling - How lung function normally reduces gradually with age and that smoking can damage lungs as if they are aging more rapidly than normal.
* Personalized letter
Results
* Follow-up was 89%
* Quit rates at 12 months in the intervention and control groups, respectively, were 13.6% and 6.4%
* Difference -7.2%, P=0.005, 95% confidence interval 2.2% to 12.1%
* NNT( number needed to treat) = 14
* People with worse spirometric lung age were no more likely to have quit than those with normal lung age in either group.
* Cost per successful quitter was estimated at £280 (€366, $556).
* A new diagnosis of obstructive lung disease was made in 17% in the intervention group and 14% in the control group.
Outcome
* Primary outcome- cessation of smoking by salivary cotinine testing 12 mos after recruitment
* Secondary outcomes –
* Changes in daily consumption of cigarettes
* Identification of new diagnoses of COPD
Limitations
* Outcome data limited to point-prevalence abstinence.
* The study does not compare the effect of patient counseling with visual/graphical communication of lung age. The study compares FeV1 with lung age which points to the fact that patients tend to understand simpler terms and images than complicated parameters like FeV1.
* The additional verbal and graphical interaction given to the intervention group as compared to minimal interaction given to the control may have biased the outcome.
* The study included a very select population from a distinct geographic area of UK.
* Practical application of the Lung age formula in the clinics.
The Lung Age calculator
Conclusion
* Informing smokers of their lung age significantly improved the likelihood of them quitting smoking, but the mechanism by which this intervention achieves its effect is unclear.
Discussion
* The results only support the conclusion that for smokers over 35 yrs who undergo spirometry, communication about lung age is a more effective motivator for tobacco cessation than uninterpreted spirometry measurements.
* Decision- wait for a trial comparing the potential benefit for smoking cessation of spirometry testing using lung age feedback vs no spirometry testing? Or adopt this method?
References
Smoking quit rate.ppt
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