Smokers who were told their “lung age” after spirometry had more than double the rate of quitting 12 months later than did smokers who were given only a clinical measure of lung performance, according to data from a randomized controlled trial.
Awareness of lung age seems to be as effective as is nicotine replacement, counseling, and bupropion in spurring smokers to quit—and it is also cheaper, the authors noted in their study.
Dr. Gary Parkes of the Limes Surgery, Hoddesdon, England, and colleagues enrolled 561 current smokers from five primary care practices in one English county. Patients were at least 35 years old (mean age, 53 years) and did not have a history of lung disease or use supplemental oxygen. All were given a series of spirometric tests, were advised during the visit to quit smoking, and were offered referral to a support service.
Each patient was randomized to receive one of two types of information: Those patients in the intervention group received an individualized explanation of their level of forced expiratory volume in 1 second (FEV1), along with a verbal explanation of their lung age and a graphic explaining the concept of lung age. Lung age was calculated using a previously established formula. (See box.) Patients in the control group received only a letter indicating their FEV1 score, with no further explanation.
In each group, the average number of cigarettes smoked daily was 17. The mean number of pack-years was 30 in the control group (281 persons) and 31 in the intervention group (280 persons).
At 12 months, there were 249 control participants, 32 having been lost to follow-up. In the intervention group, there were also 249 patients remaining, with 31 lost to follow-up. However, those lost to follow-up were included as if they had continued to smoke. In the controls, there were 18 patients (6%) who quit smoking, as verified by carbon-monoxide breath testing. In the intervention group, 38 patients quit (14%).
The investigators analyzed the data in the intervention group to determine if those with a greater lung-age deficit were more likely to quit than those with a smaller deficit or none. Contrary to previously published findings, they found no significant difference in quit rates based on disclosed lung damage, although they cautioned that the study was not powered to detect such a difference. (BMJ 2008 March 6 [Epub doi:10.1136/bmj.39503.582396.25]).
“This apparent win-win situation might explain the apparently paradoxical finding that knowing one's lung age helps a smoker to quit,” the authors wrote. “If lung age is normal, there is an incentive to stop before it is too late. If lung age is abnormal, this is a clear message the lungs are undergoing accelerated deterioration that would be slowed if the smoker stopped.”
The researchers disclosed no potential conflicts of interest.
How to Calculate aPatient's Lung Age
▸ For men: Lung age = (2.87 × height [in inches]) - (31.25 × observed FEV1 [in liters]) - 39.375
▸ For women: Lung age = (3.56 × height [in inches]) - (40 × observed FEV1 [in liters]) - 77.28