Potential clinical implications of targeted spirometry for detection of COPD: A contemporary population-based cohort study

Background: Early diagnosis of chronic obstructive pulmonary disease (COPD) through targeted spirometry may provide better treatment opportunities and in the long run reduce its high burden. We therefore investigated potential beneficial clinical implications of targeted spirometry for detection of COPD and focus on both pulmonary and extrapulmonary conditions in a contemporary general population cohort.
Methods: We recruited 29,678 randomly selected adults from the Copenhagen General Population Study from 2014-2017. Individuals unlikely to have undiagnosed COPD with a treatment potential were excluded (age <40 or >80, no smoking or respiratory symptoms, previous COPD/asthma diagnosis). COPD was defined as pre-bronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC)<0.70 and FEV1<80% of predicted.
Results: 5520(19%) were at high risk of undiagnosed COPD, of whom 589(11%) fulfilled our COPD criteria. Of these, 45% were smokers, 23% reported modified Medical Research Council dyspnoea scale (mMRC)≥2, 49% reported COPD assessment test (CAT)≥10, and 12% reported low physical activity. In addition, 8% were underweight, 28% were obese, 28% had undiagnosed hypertension, 49% had undiagnosed hypercholesterolemia, and 1% had undiagnosed diabetes. When all treatable conditions were considered, only 6.5% of individuals with undiagnosed COPD had no potentially treatable condition, while 73% had at least two treatable conditions.
Conclusions: In a general population setting, one undiagnosed COPD case will be detected for every tenth spirometry in smokers with respiratory symptoms. Up to half of individuals with undiagnosed COPD could potentially benefit from smoking cessation, treatment of respiratory symptoms, increased physical activity, and treatment of other undiagnosed comorbidities.