Prevalence of Chronic Airway Obstruction in Subjects With a History of Cigarette Smoking in a Primary Care Setting

The incidence of COPD is increasing throughout the world, with the vast majority of patients with the disease remaining undiagnosed (Coultas et al., 2001) and underreported (Frank et al., 2006; Global Initiative for Chronic Obstructive Lung Disease [GOLD], 2003; Peña et al., 2000; Takahashi et al., 2003; Van Weel et al., 2002). This is highlighted in a recent study that found 63% of patients with a smoking history and spirometry-confirmed COPD had no mention of COPD in their medical records (Frank et al., 2006). These findings are indicative of a low awareness of the condition among patients with COPD (Stratelis et al., 2004).

The use of patient-completed questionnaires to assess smoking history and status, respiratory symptoms, and socioeconomic status is a reliable and valid method of screening for COPD diagnosis and severity (Bednarek et al., 2008). The range of conditions described as COPD has led to confusion about disease terminology and difficulty with diagnosis and communication, particularly in primary care (Fukuhara et al., 2005; Kesten and Chapman, 1993). Considering that approximately 80% of patients diagnosed with COPD are current and previous cigarette smokers, mass screening of these populations using office-based spirometry becomes an attractive option (Furguson et al., 2000). A questionnaire designed to capture patient answers specific to their disease condition could provide invaluable information, which, if it correlates adequately with spirometry, could markedly improve diagnosis and provide avenues for appropriate treatment decisions. There are data supporting the argument that the prevalence of physician-diagnosed COPD is much lower than the prevalence suggested by results of population-based spirometric surveys (Chapman, 2004; Fukuchi et al., 2004; Peña et al., 2000; Soriano et al., 2000). Evidently, the development of a practical and reliable tool could help bridge the gaps in diagnosis and disease awareness. Moreover, prevalence studies underscore the need to improve awareness of COPD among cigarette-smoking populations and to provide information that could potentially lead patients to seek treatment. Hence, there is a need to develop a screening questionnaire able to identify patients at risk of airflow obstruction, for further evaluation. The LFQ, developed for this purpose, consists of a series of questions pertaining to COPD risk factors and symptoms.

Specifically, this study will aim to identify patients at risk of airflow obstruction as identified by the LFQ, the results of which will be followed for confirmation through subsequent spirometry in a subset of subjects. The LFQ will be evaluated against the spirometry results comparatively. A minimum age limit of 30 years is selected for subject participation in this study for further validation of the LFQ and to ascertain the enrollment of an adequately representative subset of subjects who may be bronchitic or asymptomatic for COPD, for comparison purposes with subjects with COPD. The study of this subject population may increase the sensitivity of COPD diagnosis and potentially provide information that could improve disease awareness and, as a consequence, possibly lead to optimization of disease management in primary care.

This is a cross-sectional study to determine the prevalence of symptomatic airway obstruction using the LFQ as a screening tool in primary care patients with a history of cigarette smoking and to provide descriptive data of this patient population. The study design is multicenter, cross-sectional, and involves a single visit. This study is not intended to evaluate the efficacy or safety of any investigational products. Following completion of written informed consent, eligible study subjects will complete a single study visit encompassing all required study assessments. Study subjects will not receive blinded study medication for evaluations of efficacy and safety.

All eligible patients will complete a self-administered Web survey that will include the LFQ. To meet both the primary and secondary aims, all patients with LFQ ≤ 18 (current cut-off for obstruction), as well as 5% of patients who score > 18, will be candidates for spirometric assessment. Only this subset of patients will undergo pulmonary function tests. Albuterol will be self-administered for determination of post-bronchodilator forced expiratory volume in one-second (FEV1)/forced vital capacity (FVC) ratio and post-bronchodilator FEV1 percentage of predicted normal. The study will end when 800 patients have been assessed spirometrically or 3,000 patients have completed the LFQ (whichever criterion is achieved first).

Prior to implementation of the full study, a pilot study will be conducted at two of the chosen study sites to pretest the proposed study procedures.