Ethnic Inequalities in COPD Outcomes: a Register-Based Study in Copenhagen, Denmark

The aim of this study was to investigate the differences in age at diagnosis and survival time after diagnosis between Chronic Obstructive Pulmonary Disease (COPD) patients with native Danish and other ethnic backgrounds. Individuals diagnosed with COPD in a hospital setting in Copenhagen in the period 2003–2007 were identified from annual hospital contact records. The cohort was restricted to COPD patients older than 35 years old at diagnosis. Follow-up was available until the end of 2010. ANOVA was conducted to test if mean age at diagnosis differed between the patient groups with different ethnicity. Kaplan-Meier estimator was used to estimate survival time after diagnosis. Cox proportional hazards models were conducted to calculate hazards of death according to ethnicity. A total of 2845 COPD patients were included; 131 (4.6%) were with non-Western ethnic minority backgrounds. Patients with non-Western ethnic backgrounds were diagnosed at a younger age and had a better survival probability compared to ethnic Danish patients; hazard ratio HR (95% CI) for death during follow-up in non-Western vs. ethnic Danish patients was 0.33 (0.18–0.62). Our study showed marked differences in age at diagnosis and survival time after diagnosis between the COPD patients with different ethnic backgrounds residing in Copenhagen. Further studies are needed to find out the reasons for younger age of COPD diagnosis in non-Western minorities and for shorter survival time after diagnosis in ethnic Danish COPD patients.