Opportunistic screening for COPD in primary care: a pooled analysis of 6,710 symptomatic smokers and ex-smokers

Abstract

Objective

To investigate the prevalence and predictors of COPD in a large cohort of symptomatic smokers and ex-smokers in a primary care setting.

Methods

General practitioners (n=390) consecutively recruited individuals ≥35 years, with current or previous tobacco exposure, at least one respiratory symptom, and no previous diagnosis of obstructive airways disease; and obtained data on tobacco exposure, body mass index (BMI), and dyspnea (Medical Research Council dyspnea scale). All individuals with airflow obstruction, ie, FEV ₁/FVC <0.70 at initial lung function test, had diagnostic spirometry, including bronchodilator reversibility test. COPD was defined as respiratory symptom(s), tobacco exposure, and nonreversible airflow limitation.

Results

Of the 6,710 at-risk individuals screened with spirometry (52% male sex, mean age 58 years [SD 10.9]), 1,185 were diagnosed with COPD (17.7%). Apart from age and pack-years, multivariate logistics regression analysis, adjusted for FEV ₁, revealed that BMI <25 kg/m ² (OR 4.2, 95% CI 3.0–5.9, p<0.001), BMI 35+ kg/m ² (OR 1.6, 95% CI 1.2–2.3), self-reported dyspnea (OR 1.2, 95% CI 1.1–14, p=0.04), wheeze (OR 1.3, 95% CI 1.1–1.6, p=0.001), phlegm (OR 1.4, 95% CI 1.1–1.6, p<0.001), and MRC ≥3 (OR 1.6, 95% CI 1.2–2.0, p=0.001) were associated with a significantly higher likelihood of being diagnosed with COPD. No association was found between sex, cough, and recurrent respiratory tract infections and a diagnosis of COPD.

Conclusion

The prevalence of COPD is high among smokers and ex-smokers with one or more respiratory symptoms seen in primary care, and the presence of wheeze, phlegm and dyspnea, together with both low BMI and obesity identify a subgroup with an even higher likelihood of COPD.