Spirometry for detection of undiagnosed chronic obstructive pulmonary disease in primary care

The aim of this study was to assess the utility of family physicians' office spirometry, to detect previously undiagnosed chronic obstructive pulmonary disease (COPD) in individuals who smoke. Furthermore, agreement between doctors with more or less experience in performing spirometry was assessed.

Cross-sectional study. Smokers aged 40-69 years who attended a family practice centre were invited to participate. Variables considered were tobacco pack-years, time of tobacco use, smoking cessation, COPD symptoms, Medical Research Council Dyspnoea Scale values, pre- and post-bronchodilator spirometry data, and acceptability of spirometry curves.

212 subjects underwent spirometry, and 179 yielded acceptable spirometry curves. Of these, 173 subjects underwent reversibility testing, of whom 39 (22.5%, 95% CI: 16.2-29.1%) were diagnosed as COPD. Of these, 48.7% were classified as COPD Stage I and 41.0% as Stage II following GOLD criteria. Age, gender, pack-years and cough were related to airflow obstruction levels. Symptom number was not related to presence of airflow obstruction. More than 80% of spirometry curves were acceptable. Agreement on curve acceptability between junior doctors and a family physician trainer was very good, but moderate between junior doctors and a pulmonologist.

Forced spirometry data from smokers attending general practice doctors can be used to identify a significant number of previously undiagnosed COPD cases.