Comorbidities of COPD have a major impact on clinical outcomes, particularly in African Americans.

Background: COPD patients have a great burden of comorbidity. However, it is not well established whether this is due to shared risk factors such as smoking, if they impact patients exercise capacity and quality of life, or whether there are racial disparities in their impact on COPD.

Methods: We analyzed data from 10,192 current and ex-smokers with (cases) and without COPD (controls) from the COPDGene cohort to establish risk for COPD comorbidities adjusted for pertinent covariates. In adjusted models, we examined comorbidities prevalence and impact in African-Americans (AA) and Non-Hispanic Whites (NHW).

Results: Comorbidities are more common in COPD compared to those with normal spirometry (controls), and the risk persists after adjustments for covariates including pack-years smoked. After adjustment for confounders, eight conditions were independently associated with worse exercise capacity, quality of life and dyspnea. There were racial disparities in the impact of comorbidities on exercise capacity, dyspnea and quality of life, presence of osteoarthritis and gastroesophageal reflux disease having a greater negative impact on all three outcomes in AAs than NHWs (p<0.05 for all interaction terms).

Conclusions: Individuals with COPD have a higher risk for comorbidities than controls, an important finding shown for the first time comprehensively after accounting for confounders. Individual comorbidities are associated with worse exercise capacity, quality of life, and dyspnea, in African-Americans compared to non-Hispanic Whites.