Aims: To evaluate the prevalence and predictors of airflow limitation among smokers aged > or =40 years visiting primary care practices in Switzerland, and the correlation between airflow limitation and patient-reported symptoms.
Methods: General practitioners (GPs) were invited to participate in the study via letter. Airflow limitation was measured using an EasyOne spirometer without administration of a bronchodilator, and patient-reported symptoms were evaluated using an interviewer-administered questionnaire.
Results: 15,084 subjects recruited by 440 GPs had acceptable quality spirometry traces; 8,031 of these (53%) had symptom data available and were included in this analysis. Only 18.5% of the GP consultations were for respiratory reasons. In total, 29% of individuals had pre-bronchodilator airflow limitation suggesting chronic obstructive pulmonary disease according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD)/Hardie interpretation. The interviewer-administered questionnaire indicated that 58% of individuals had at least one current symptom - cough, sputum production, or dyspnoea. There were no differences in lung function for patients answering yes or no to symptom questions.
Conclusions: Pre-bronchodilator airflow limitation and patient-reported respiratory symptoms are frequent among smokers, but short dichotomous questions about symptoms are not useful for identifying patients with airflow limitation. Spirometry can identify patients with early airflow limitation in general practice. However, poor quality of spirometry, even with an automated feedback and quality control spirometer, remains an issue.