Quality of spirometry in primary care: a focus on clinical use

Background: Spirometry is increasingly used in primary care. Quality of spirometry is traditionally assessed using the American Thoracic Society (ATS) and European Respiratory Society (ERS) criteria. It is unknown if the quality of spirometry is sufficient for daily clinical use. Aim: To assess the proportion of clinically useful spirometry tests in primary care and to evaluate whether the quality of spirometry in general practices is sufficient for daily clinical use. Methods: In this prospective observational study, general practitioners (GPs) included 10 consecutive spirometry tests of patients who underwent spirometry as part of usual care. Patients completed a medical history questionnaire including ACQ, CCQ and MRC. GPs and two pulmonologists assessed the spirometry tests including the questionnaires on quality and usefulness and formulated a diagnosis. Two lung function analysts assessed if the tests met ATS/ERS criteria. Agreement on diagnosis (asthma, COPD, no respiratory disease, other) was assessed using Cohen’s kappa (κ). Results: Spirometry tests of 149 participants covering 15 GPs were included of which 20 tests (13%) met ATS/ERS criteria. GPs and pulmonologists rated ≥88% of the tests as clinically useful and ≥80% as being of good quality. Agreement on diagnosis between the pulmonologists (56%; κ 0.38, 95%CI 0.27 to 0.50) did not differ from agreements between GPs and pulmonologist 1 (56%; κ 0.39, 95%CI 0.22 to 0.44) and 2 (59%; κ 0.44, 95%CI 0.32 to 0.55). Conclusion: Although few spirometry tests met ATS/ERS criteria, clinical usefulness was very high as rated by both GPs and pulmonologists. This suggests that according to physicians, meeting the ATS/ERS criteria is not required for providing a diagnosis.