Published Online: September 15, 2016
Chronic obstructive pulmonary disease (COPD) is a common lung disease characterized by a range of clinical features and variable course and response to therapy. Identification of subgroups of individuals that share common features of this condition is termed COPD phenotyping. Little is known about the natural history of COPD that has developed from airway remodelling due to asthma, as compared to other COPD phenotypes, such as COPD that has developed from smoking. There have been few studies that have examined the effects of a history of asthma on long-term COPD health outcomes and their results have been conflicting.
In a population-based cohort study recently published in The Journal of Allergy & Clinical Immunology (JACI), Gershon and colleagues hypothesized that individuals with COPD and a history of asthma were at higher risk of long-term adverse outcomes, such as COPD, respiratory and cardiovascular (CV) related hospitalizations and mortality, than those without.
They followed all individuals with physician-diagnosed COPD between ages 40 and 55 in the province of Ontario, Canada (population approximately 13 million) for up to 5 years. They compared the hazards of COPD, respiratory and CV related hospitalizations and all-cause mortality between groups with and without history of asthma controlling for demographic characteristics, comorbidities and level of health care. Among 9,053 individuals with COPD included in this study, 2,717 (30%) had a history of asthma, providing a useful population to study.
The authors found that the individuals who had a history of asthma had a 53% and 63% higher hazard of COPD- and respiratory hospitalizations, respectively, than those without history of asthma. Further, individuals with more severe asthma did worse than those with milder asthma. However, the history of asthma was not associated with a higher hazard of CV hospitalizations or all-cause death.
The results of this study teach us about COPD that has developed from asthma and can be used to alert clinicians of this high risk group. They are a step towards creating personalized COPD preventive and management strategies that improve health outcomes.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.