Predictors of COPD in symptomatic smokers and ex-smokers seen in primary care

Even in subjects at high risk of chronic obstructive pulmonary disease (COPD), the diagnosis is often missed due to lack of awareness of symptoms and risk factors. The objective of this study was to identify predictors of a diagnosis of COPD in symptomatic current and ex-smokers seen in a primary care setting. General practitioners ( n = 241) consecutively recruited subjects ≥ 35 years, with tobacco exposure, at least one respiratory symptom (i.e. cough, sputum, wheeze, dyspnoea and/or recurrent lower respiratory tract infections), and no previous diagnosis of obstructive airways disease. Information on age, smoking status, body mass index (BMI) and dyspnoea (Medical Research Council (MRC) dyspnoea scale) was obtained. Individuals with airway obstruction (i.e. forced expiratory volume in 1 second (FEV₁₎/forced vital capacity ratio (FVC) < 0.70) at initial spirometry had a diagnostic spirometry after administration of a bronchodilator. COPD was defined as the presence of symptoms, tobacco exposure and persistent airflow limitation. The most prevalent symptoms were cough (72%) and dyspnoea (48%). Of 3875 (50% females, mean age 57 years) subjects screened, 700 (18.1%) were diagnosed with COPD. Multivariate logistic regression analysis revealed that increasing age 50-59 years (OR 2.4, 95% CI 1.8-3.3), 60-69 years (OR 4.1, 95% CI 3.1-5.5), ≥70 years (OR 5.7, 95% CI 4.2-7.8), BMI < 25 (OR 2.3, 95% CI 1.9-2.7), being current smoker (OR 1.2, 95% CI 1.01-1.5), self-reported dyspnoea (OR 1.7, 95% CI 1.4-2.0), wheeze (OR 1.9, 95% CI 1.5-2.3) and sputum (OR 1.4, 95% CI 1.1-1.7) were associated with a significantly higher risk of being diagnosed with COPD. No association was found between gender, cough and recurrent respiratory tract infections and a diagnosis of COPD. Among symptomatic smokers and ex-smokers seen in primary care, self-reported sputum production, wheeze, dyspnoea and low BMI identify a subgroup with a higher likelihood of COPD.