Telling Smokers Their Lung Age Motivates Quitting

By Judith Groch
HERTFORDSHIRE, England, March 7 -- A simple lesson in how smoking prematurely ages lungs was twice as effective in getting patients to quit as was an FEV1 result with no explanation, a study here found.
Telling smokers their spirometry-estimated lung age as part of an intervention was associated with a smoking reduction of 7.2%, compared with a group given only their raw FEV1 results, Gary Parkes, M.D., of Limes Surgery, a private practice here, and colleagues reported in BMJ Online First.
"Given the heavy health and economic burden of smoking, we believe that formal economic evaluation of this new and simple intervention should be a research priority," they wrote.
The findings came from a search of the computerized records of five general practices in Hertfordshire, near London. The review identified 561 patients older than 35 recorded as smokers in the previous 12 months. Recruitment started in February 2004 and follow-up was completed in March 2007.
All participants were offered spirometric assessment of lung airflow, after which they were randomized to intervention or control groups.
However, intervention participants received their results in terms of "lung age," defined as the age of the average healthy individual who would perform similarly on spirometry.
They also received detailed individual information about the spirometry results and their lung age, were given pictorial evidence in the form of a diagram showing how smoking ages the lungs, and were told that quitting would slow the damage.
Those in the control group received a raw figure for forced expiratory volume (FEV1), but nothing more.
Both groups were told that their lung function would be measured again after 12 months, and all were advised to quit and were offered referral to local smoking cessation services.
The primary outcome was verified cessation of smoking by salivary cotinine testing 12 months after recruitment.
Follow-up included 89% of the patients. Independently verified 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%, number needed to treat 14).
However, a subgroup analysis found no dose-response relation between "lung-age deficit" (lung age minus chronological age) and the outcome, as quitters and non-quitters had similar lung deficits.
People with worse spirometric lung age were no more likely to quit than those with normal age in either group.
This unexpected finding, the researchers said, suggests that knowing one's lung age helps a smoker quit whatever the results.
The mechanisms by which this intervention achieved its effect are unclear, and further research is needed to explain the psychological forces active in successful quitting in different circumstances.
The cost per successful quitter was estimated at $556, the researchers said. These estimates suggest that lung age is of comparable effectiveness, and potentially cheaper, than other currently available treatments, including nicotine replacement therapy and various forms of counseling.
A new diagnosis of obstructive lung disease was made in 17% of patients in the intervention group and in 14% of the controls for a total of 16% (89) of the participants.
In an accompanying editorial, Raphaёl Bize, M.D., and Jacques Cornuz, M.D. of the University of Lausanne in Switzerland, wrote that on the basis of the evidence so far, primary care practitioners have to decide whether to wait for a trial comparing the potential benefit for spirometry testing versus no such testing or whether to adopt the strategy suggested by Dr. Parkes and colleagues.
In making the decision, they should be aware of certain limitations of the trial including the lack of information about the comparability of the study sample with the entire recruitment population, the longer duration of contact between participants and caregivers in the intervention group, and outcome data limited to point-prevalence abstinence.
Despite these limitations, they said the strategy described here seems to be the best option so far for communicating the results of spirometry. This method might also be an opportunity for general practitioners to tailor smoking cessation messages to individual patients.
The study was supported by a leading practice through research award from the Health Foundation. The study authors and editorialists declared no competing financial interests.
Primary source: BMJ Online FirstSource reference:Parkes G, et al "Effect on smoking quit rate of telling patients their lung age: the Step2quit randomized controlled trial" BMJ Online First 2008: DOI:10.1136/bmj.39503.582396.25. Additional source: BMJ Online FirstSource reference: Bize R, Cornuz J "Incentives to quit smoking in primary care" BMJ Online First 2008: DOI: 10.1136/bmj.39503.582396.25.