Effectiveness of Spirometry as a Motivational Tool for Smoking Cessation

A Clinical Trial, the ESPIMOAT Study

María Isabel Irizar-Aramburu; Jose Manuel Martínez-Eizaguirre; Petra Pacheco-Bravo; Maria Diaz-Atienza; Iñigo Aguirre-Arratibel; Maria Isabel Peña-Peña; Mercedes Alba-Latorre; Mikel Galparsoro-Goikoetxea

Disclosures

BMC Fam Pract. 2013;14(185) 

In This Article

Background

Smoking is the main cause of preventable mortality and morbidity in industrialized countries. It is estimated that in Spain, as many as 56,000 people die every year due to smoking.[1] It is one of the main risk factors for vascular and respiratory diseases and a causative agent for chronic obstructive pulmonary disease (COPD), accelerating the physiological worsening of the lung volume in susceptible smokers.[2,3] COPD is a disease with a high prevalence (10.2% in 40- to 80-year-olds) and a high rate of under-diagnosis (72% of those with COPD not having been diagnosed), according to the EPISCAN study.[4] It is the fifth cause of death in Spain and one of the main causes of morbidity, responsible for a profound worsening in quality of life, especially in advanced stages of the disease.[5] The World Health Organization (WHO) predicts that by 2030, COPD will go from 12th to 5th place in the list of most prevalent diseases in the world, and from 6th to 3rd place in terms of mortality.[6] These data justify the Spanish National Health System launching a strategy against COPD in 2009[7] focused around smoking cessation interventions.

Smoking is the main cause of COPD, being associated with more than 80% of cases. According to a study by Fletcher et al.,[2] 15 to 20% of smokers develop COPD, more recent studies[8,9] arguing that the figure may in fact be as high as 50%. After the results of the Lung Health Study[10] in 1994, a randomized clinical trial that demonstrated that an intensive anti-smoking intervention in patients with mild and moderate COPD managed to halt the decline in FEV1, several consensus statements have recommended spirometry testing in smokers to benefit their general health. In 2000, one of the main sponsors of the screening programs for COPD was the American National Lung Health Education Program (NLHEP)[11] who advocated the use of spirometry for COPD screening in all patients with any respiratory signs and in smokers aged over 45 years old. COPD meets some of the criteria proposed by Frame and Carlson[12] to justify a screening program, that is, it is an important health problem with an long initial asymptomatic stage; there is a screening test with high sensitivity and specificity, namely spirometry, which is considered the gold standard for the diagnosis; and there is a treatment that, if administered in the asymptomatic stage, is effective in reducing overall morbidity and mortality, in this case smoking cessation.[2]

Any screening test must have a good cost-effectiveness ratio. The cost-effectiveness of spirometry depends on various factors, such as the number of patients that need to be screened to detect one case of COPD or, better, to result in one person stopping smoking. In the Lung Health Study,[10] the most significant results were obtained in middle-aged patients (mean age of 48 years), with mild or moderate COPD (mean post-bronchodilator FEV1 of 78%), most of whom did not consider themselves "ill": patients from the anti-smoking intervention group had a smaller decrease in FEV1, the authors concluding that spirometry is cost-effective since it permits the early detection of COPD and focusing measures on these patients. Other authors[13] concluded that even modest quit rates attributable to spirometry may be cost-effective, although the authors comment that further studies are required to assess the independent role of spirometry in smoking cessation.

Later, in 2005, the American Agency for Healthcare Research and Quality (AHRQ) published a systematic review[14] concluding that the benefits of spirometry for opportunistic screening to detect COPD in smokers and ex-smokers will remain unclear until it is demonstrated that spirometry contributes to increasing the number of patients who quit smoking. This review included seven clinical trials of which only one[15] assessed the independent contribution of spirometry in smokers and, though they found the quit rate was higher among those who underwent spirometry as well as receiving advice (6.5 vs. 5.5% in those who only received advice), the difference was not significant. The authors of this review also indicated the need for further studies to determine the role of spirometry in smoking cessation. Another systematic review, that of the U.S. Preventive Services Task Force (USPTF) published in 2008,[16] a subsequent systematic review[17] and a 2005 Cochrane review, on the efficacy of assessing biomedical risks (among them pulmonary function) as a tool for quitting smoking,[18] all concluded that the evidence of a role of spirometry as a motivational tool to encourage smoking cessation is inconclusive, as most studies had a short follow-up period and significant limitations, such as not assessing the independent role of spirometry and insufficiently large sample sizes.

A 2012 updated review of the Cochrane Collaboration[19] found little scientific evidence of an effect on quitting smoking for most biomedical tests. Out of the 15 studies included, only 2 of them detected a significant effect: a trial based on ultrasound of carotid and femoral arteries and another on spirometry combined with information on test results in terms of "lung age"[20] which found a significant improvement in the smoking cessation success rate compared to the control group that did not receive the spirometry test report (RR 2.12; CI 95% 1.24 to 3.62). Nevertheless, this study still did not assess the independent role of spirometry, as testing was used in both the experimental and control groups.

Based on the available evidence, the executive summary of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) published in 2013,[21] the international reference, the guidelines of the Spanish Society of Family and Community Medicine and the Spanish Society of Pulmonology and Thoracic Surgery (semFYC-SEPAR)[22] and the 2012 Spanish guidelines for COPD (GesEPOC)[23] advocate "opportunistic" case finding by spirometry only in smokers with respiratory symptoms. However, there is no consensus on this strategy in the scientific community, some authors questioning the usefulness of COPD screening in asymptomatic smokers due to the weak correlation between these symptoms in smokers and COPD. A cohort study,[24] including 3,955 people in the USA recruited between 1980 and 2008, that attempted to assess the association between respiratory symptoms and airflow obstruction, confirmed the under-diagnosis of airway obstruction in smokers and concluded that respiratory symptoms have low sensitivity, specificity, and positive and negative predictive values for diagnosing COPD, given that these symptoms are common in smokers with and without airway obstruction; on this basis, the authors advocate spirometry testing in all smokers older than 40 years of age with a more than 20 pack-year history of smoking with or without respiratory symptoms.

Therefore, given the available evidence and the lack of high quality clinical trials assessing the independent role of spirometry in smoking cessation, and that discovering they have COPD may help people quit smoking, we believe that the study we propose may be useful to clarify various issues. Specifically, if our hypothesis were to be correct and spirometry testing did help people quit smoking, public health authorities would have a basis on which to promote this strategy, as it would have the potential to change lifestyles and thereby prevent highly prevalent medical conditions such as various types of cancer and cardiovascular disorders, as well as COPD. Additionally, if a significantly higher rate of smokers with an early diagnosis of COPD quit smoking than those with no diagnosis of airway obstruction, the demonstrated beneficial effect in terms of reducing morbidity and mortality due to COPD, would in itself justify the screening. If, on the other hand, no significant effect on smoking cessation were detected, there would be no arguments supporting COPD screening by spirometry, and we should probably stop performing spirometry tests for this purpose, thus avoiding an unnecessary use of resources. The protocol we present here aims to provide evidence to address this issue, by attempting to determine whether conducting spirometry testing to screen for COPD and informing individuals about their results is effective in encouraging smoking cessation in smokers older than 40 years of age with a more than 10 pack-year history.

Objectives

The primary objective of this study is to assess the effectiveness of spirometry testing together with providing patients with information about their results for smoking cessation after 1 year in people older than 40 years of age with a more than 10 pack-year history who have not been diagnosed with COPD (at the outset of the study). The secondary objectives include comparing the quit rates in patients with a new diagnosis of COPD and those with normal lung function, and comparing the change in daily smoking rate between the intervention and control groups.

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