Factors associated with undiagnosed COPD in patients hospitalised for severe COPD exacerbation

Abstract

Background Studies suggest that up to 70% of chronic obstructive pulmonary disease (COPD) cases globally are undiagnosed worldwide. Some of these undiagnosed patients may present with severe exacerbation and factors associated with underdiagnosis in this population are unknown. We investigated the key factors associated with underdiagnosis in two cohorts of patients hospitalised for severe COPD exacerbation at different time points.Methods This retrospective, multicentre study analysed data from patients hospitalised for COPD exacerbation at two independent centres during two distinct time periods: between 1 January 2017 and 31 December 2018 in the Aquitaine region and between 1 January and 31 December 2022 in Paris. Undiagnosed COPD was defined as the absence of pulmonary function testing before the index exacerbation. Multivariate logistic regression was used to evaluate associations between underdiagnosis and patient characteristics.Results Among the 424 patients, 93 (21.9%) were undiagnosed before hospitalisation, with a stable rate over time (22% in 2017–2018 and 21% in 2022). Multivariate analysis revealed that underdiagnosis was related to higher forced expiratory volume in one second (FEV1; adjusted OR (aOR)=1.02, p=0.043) and female sex (aOR=1.91, p=0.015). Patients with undiagnosed COPD had significantly lower rehospitalisation and mortality rates. After the initial severe exacerbation, higher mortality was associated with a higher Charlson Comorbidity Index (HR=1.24, p=0.007) and older age (HR=1.05, p=0.008).Conclusion This retrospective, multicentre study demonstrated that about 20% of patients admitted with severe exacerbation were undiagnosed for COPD. Higher FEV1 and female sex were associated with underdiagnosis, emphasising the need for special attention to this population. These findings highlight the need to improve training and access to spirometry and develop new diagnostic tools that facilitate earlier detection and management of COPD.