Many patients with chronic obstructive pulmonary disease (COPD) are diagnosed late, e.g., at first acute exacerbation of COPD (AECOPD). AECOPD increases the risk of death. We aim to investigate patient characteristics and mortality across diagnostic settings among patients with COPD.

This nationwide Danish study allocated 107,023 patients with a first-time registered COPD-related hospital contact between 2010 and 2018 based on diagnostic setting: primary care (prior inhalation medication use), hospital outpatient clinic or hospital admission. Multivariable logistic regression was employed to investigate patient characteristics and mortality across these diagnostic settings.

In total, 81,035 (75.7 %) patients were diagnosed in primary care, median age 63 years (interquartile range (IQR) 53–71); 11,302 (10.6 %) at an outpatient clinic, median age 68 years (IQR 60–76), and 14,686 (13.7 %) during hospital admission, median age 73 years (IQR 65–81). Patient characteristics associated with diagnosis during hospital admission encompassed age (odds ratio (OR) 1.05, 95 % confidence interval (CI) 1.05–1.05, p < 0.001), male sex (OR 1.14, CI 1.10–1.19, p < 0.001), and number of comorbidities, which increased from one comorbidity (OR 2.64, CI 2.50–2.79, p < 0.001) to six or more comorbidities (OR 12.37, CI 11.26–13.60, p < 0.001). Diagnosis during hospital admission due to AECOPD was associated with increased one-year mortality (OR 1.24, CI 1.16–1.33, p < 0.001) compared to diagnosis in primary care.

Patients diagnosed with COPD in hospital settings were generally older, predominantly male, and had more comorbidities. Patients diagnosed in primary care prior to their first AECOPD admission had higher one-year survival.