Quality of spirometry in primary care for case finding of airway obstruction in smokers.

BACKGROUND Diagnosis of chronic obstructive pulmonary disease (COPD) and its severity determination is based on spirometry. The quality of spirometry is crucial. OBJECTIVES Our aim was to assess the quality of spirometry performed using a spirometer with automated feedback and quality control in a general practice setting in Switzerland and to determine the prevalence of airflow limitation in smokers aged > or =40 years. METHOD Current smokers > or =40 years of age were consecutively recruited for spirometry testing by general practitioners. General practitioners received spirometry training and were provided with an EasyOne spirometer. Spirometry tests were assigned a quality grade from A to D and F, based on the criteria of the National Lung Health Education Program. Only spirometry tests graded A-C (reproducible measurements) were included in the analysis of airflow limitation. RESULTS A total of 29,817 spirometries were analyzed. Quality grades A-D and F were assigned to 33.9, 7.1, 19.4, 27.8 and 11.8% of spirometries, respectively. 95% required < or =5 trials to achieve spirometries assigned grade A. The prevalence of mild, moderate, severe and very severe airway obstruction in individuals with spirometries graded A-C was 6, 15, 5 and 1%, respectively. CONCLUSION Spirometries in general practice are of acceptable quality with reproducible spirometry in 60% of measurements. Airway obstruction was found in 27% of current smokers aged > or =40 years. Office spirometry provides a simple and quick means of detecting airflow limitation, allowing earlier diagnosis and intervention in many patients with early COPD.