Misdiagnosis of Asthma and COPD and Underuse of Spirometry in Primary Care Unselected Patients

Background: The diagnosis of both asthma and chronic obstructive pulmonary disease (COPD) consists of a combination of classical symptoms and signs, and the evidence of consistent lung function abnormalities. Spiromety has been reported to be underused, possibly for practical difficulties in accessing to a lung function lab. This may lead to misdiagnosis of both asthma and COPD. We aimed to evaluate the frequency of spirometry use and the concordance between doctor-diagnosed asthma and COPD and spirometric patterns, in an unselected cohort of patients sent by general practitioners to perform a spirometry.

Methods: The first 300 patients consecutively enrolled patients performed spirometry and bronchodilator test with salbutamol 400 mcg. Demographic, clinical and lung function data have been collected.

Results: 128 patients (42.7%) declared a doctor-diagnosed asthma and 75 (25%) a doctor-diagnosis of COPD; the remaining subjects never had received any respiratory diagnosis. Only 112 patients with doctor-diagnosed asthma (55.2%) and 114 (56.2%) with doctor-diagnosed COPD have ever performed a spirometry in their entire life (average time since the last spirometry was about 47.0 months). Eighty-nine (69.5%) and 10 (13.3%) patients with respectively doctor-diagnosed asthma and COPD had concordant spirometric patterns with their known diseases.

Discussion: we described a worrying lack of use of spirometry and a high proportion of misdiagnosis, in patients with suspect chronic airway inflammatory diseases and cared by primary care physicians. Novel strategies to overcome this situation include should be implemented to give a better care to our patients.