Detecting Airflow Obstruction in Smoking Cessation Trials

1Cigarette smokingCigarette smoking has been identified as the most important risk factor for COPD, and epidemiologic surveys in Europe and the United States have demonstrated a high prevalence and rising mortality of the disease and rising mortality. The condition is insidious, and is usually diagnosed late, when lung function has already deteriorated. Since the most effective treatment for COPD is smoking cessation, the early identification of smokers most likely to have COPD develop is important in order to encourage them to stop smoking with Canadian Health&Care Mall.

Screening the general population is an effective method for detecting subjects with impaired lung function, but this option is not feasible in the daily routine of general practice. In contrast, spirometric screening of populations at risk for COPD might be a more effective method for early detection in primary health care. Studies of smokers from a semirural practice in the Netherlands, a rural village in Spain, and a primary health center in Sweden have proven successful; prevalence rates of airflow obstruction ranging from 11.5 to 22% were demonstrated. Incidentally, the Dutch study also found spirometry to be cost-effective, lasting on average only 4 min at a cost of only 5 to 10€.

Smokers participating in cessation trials might be at risk for COPD; they are usually selected because of significant cigarette consumption and are often motivated by health concerns and/or respiratory symptoms. Surprisingly enough, little attention has been paid to the assessment of lung function in cessation trials since the first smoking cessation clinics were started in Stockholm half a century ago. Although this is not necessarily a problem for those smokers who are successful in quitting smoking, it may be disastrous for those unavailable for follow-up, typically 70% of participants. Among them, subjects with airflow obstruction who continue to smoke incur the risk of accelerated decline in FEV1.

With the above considerations in mind, we therefore decided to examine the spirometric data obtained during a 1-year follow-up of participants in two cessation trials carried out recently by our team. The aim of this study was twofold: (1) to evaluate the prevalence of airflow obstruction at enrollment; and (2) to determine the proportion of smokers with airflow obstruction at enrollment who were unavailable for follow-up. In addition, we examined the impact of smoking intervention on lung function in participants who completed the trials.