Asthma is traditionally regarded as a chronic
airway disease, and recent
literature proves its heterogeneity, based on distinctive clusters or
phenotypes of
asthma. In defining such
asthma clusters, the
nature of
comorbidity among
patients with
asthma is poorly understood, by assuming no causal relationship between
asthma and other comorbid conditions, including both communicable and
noncommunicable diseases. However, emerging evidence suggests that the status of
asthma significantly
affects the increased susceptibility of the
patient to both communicable and
noncommunicable diseases. Specifically, the impact of
asthma on susceptibility to
noncommunicable diseases such as chronic systemic inflammatory
diseases (e.g.,
rheumatoid arthritis), may provide an important insight into
asthma as a
disease with systemic inflammatory features, a conceptual
understanding between
asthma and
asthma-related
comorbidity, and the potential implications on the
therapeutic and preventive interventions for
patients with
asthma. This
review discusses the currently under-recognized clinical and immunological
phenotypes of
asthma; specifically, a higher
risk of developing a systemic inflammatory
disease such as
rheumatoid arthritis and their implications, on the conceptual
understanding and management of
asthma. Our discussion is divided into three parts
literature summary on the relationship between
asthma and the
risk of
rheumatoid arthritis; potential mechanisms underlying the
association; and implications on
asthma management and
research.