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.