Using targeted spirometry to reduce non-diagnosed chronic obstructive pulmonary disease

Background: Chronic obstructive pulmonary disease (COPD) is increasing worldwide and thus its associated morbidity and mortality. However, COPD often goes undiagnosed.

Objectives: We evaluated the rate of non-diagnosed irreversible airway obstruction (AO) and characterized this patient group. We further assessed the possible effects of conducting targeted spirometry in a population sample in Salzburg, Austria, as part of the Burden of Obstructive Lung Disease (BOLD) study.

Methods: 1,258 adults ≥40 years of age completed a questionnaire and performed spirometry before and after bronchodilator therapy (post-BD). Irreversible AO was defined as post-BD FEV(1)/FVC below the lower limit of normal; we used the FEV(1)% predicted (pred.) to further grade the disease. Participants without a physician diagnosis of COPD who reported respiratory symptoms and a history of risk factors (ever smoking or occupational risk) were defined as eligible for targeted spirometry.

Results: 85.9% (171/199) of the participants with irreversible AO did not report a prior diagnosis of COPD. Non-diagnosed AO was inversely related to severity, age, self-reported prior respiratory diseases and cough as a respiratory symptom. 343 participants were eligible for targeted spirometry and irreversible AO was present in 86 (25.1%) participants. Therefore, targeted spirometry could reduce the underdiagnosis of irreversible AO of any severity by 50.3% (86 of 171). The diagnosis of 1 person with FEV(1) <80% pred. would require spirometry in 8.4 subjects (95% confidence interval 6.2-11.1).

Conclusion: Although several factors are associated with non-diagnosed AO, spirometry in individuals with respiratory symptoms and exposure to risk factors could reduce undiagnosed irreversible AO by half.