Diagnosed and underdiagnosed cases of COPD in the primary care setting: Differences and similarities.

Background: The prevalence and healthcare burden of COPD are estimated to arise over the next years not only due to persistent tobacco consumption but also due to misdiagnosis of the disease. The present observational study among smokers and ex-smokers aims to assess the prevalence of COPD misdiagnosis (over and underdiagnosis) as well as the differences and similarities between patients with previous correct diagnosis of COPD and those with underdiagnosed disease. Materials and Methods: We performed an observational cross-sectional study in four rural counties and in one of the primary health centers of the metropolitan city of Thessaloniki, Greece aiming estimate the prevalence of COPD and evaluate the differences between patients with diagnosed and underdiagnosed disease. Results: Overall, 5,239 participants were enrolled in the study, of whom 565 subjects (10.8%) fulfilled the clinical and spirometric criteria for the diagnosis of COPD according to GOLD guidelines. Notably, 264 patients had a previous correct diagnosis of COPD (46.7%), 301 patients were underdiagnosed (new cases) while 461 subjects had a previous false diagnosis of COPD (overdiagnosis). Patients with underdiagnosed COPD were younger and more frequently current smokers. In addition, they presented less frequently with clinically important respiratory symptoms estimated by specific questionnaires but on the contrary the percentages of single symptoms such as cough, phlegm, dyspnea and wheezing were not significantly different compared with those with correct prior COPD diagnosis. They also reported fewer comorbidities and they mostly had early-stage disease based on spirometry or medical history. Conclusion: There is a noteworthy number of underdiagnosed and overdiagnosed cases of COPD among an unselected sample of the general population in northern Greece. Underdiagnosed patients with COPD are younger, usually current smokers but with early-stage disease compared with previously diagnosed subjects. National screening programs for high risk populations (current smokers with respiratory symptoms) in the primary care setting as well as GPs training on spirometry and COPD management should be planed as healthcare strategies in the near future.