Severe asthma may be different form of disease to mild or moderate asthma
Severe asthma may not simply be an increase in asthma symptoms, but may be a different form of the disease altogether, according to new research published in the European
Respiratory Journal (2003;22:470).
A cross-sectional observational study of 321 patients has identified
certain features of severe asthma that are distinct from those described
for moderate or mild forms of the disease.
Patients with more severe asthma are less responsive to standard asthma
therapy, and have been shown to experience greater morbidity and a lower
quality of life than asthmatics whose disease is adequately controlled
by therapy. This subgroup of patients has been identified as being 15
times more likely to use emergency medical care than patients with mild
or moderate asthma, and 20 times more likely to require hospital admission.
Researchers from ENFUMOSA, the European Network For Understanding Mechanisms Of Severe Asthma, studied 158 patients with mild to moderate asthma,
whose asthma was controlled by low doses of inhaled corticosteroids,
and 163 patients with severe asthma, who had experienced at least one
asthma exacerbation requiring oral steroid treatment in the past year,
despite treatment with high doses of corticosteroids.
They found that females were 2.8 times more common in the severe-asthma
group than males, supporting a hypothesis that severe asthma may be a
sex-related disease. Evidence of structural changes in the peripheral
airways or alveolar walls, sub-optimal sensitivity to glucocorticosteroids,
neutrophilia and ongoing mediator release were also found to be specific
to the severe-asthma
group of patients. The researchers also found that severe asthma was
associated with an increased body mass index, and that exposure to aspirin
was a potential risk factor for severe asthma.
The authors say that severe asthma shares features with chronic obstructive
pulmonary disease, and investigation into these features is needed to
test the hypothesis that severe asthma is in fact a different disease
to mild/moderate asthma. |
