Not All Asthma Created Equal
Distinct Differences Between Severe, Mild Asthma Could Lead to Targeted Treatments
Severe Asthma Unique continued...
There was no significant difference between patients with severe and milder
asthma, however, in the length of time required to exhale a volume of air -- a
measure known as air-flow limitation.
Airflow limitation was common among asthma sufferers, regardless of whether
they had mild, moderate, or severe forms of the disease.
But there was little air trapping seen in patients with mild to moderate
disease, even when air flow limitations occurred. Conversely, patients with
severe disease had some air trapping even in the absence of airflow
"That tells us that something different is going on in people classified
as having severe asthma, either physiologically or in the airways that are
affected," Sorkness said. "It's likely that airflow limitation occurs
in the larger airways of the lungs, while air trapping is occurring in the
small airways that branch to the outer portions of the lung."
4,000 Asthma Deaths
About 4,000 people in the United States die each year from asthma, and half
a million are hospitalized, according to the latest figures from the CDC.
The 5% to 10% of patients with the most severe disease account for a
disproportionate number of deaths and the bulk of asthma-related costs to the
health care system, Wake Forest University asthma researcher Wendy C. Moore,
MD, tells WebMD.
Along with Wake Forest colleagues, Moore is studying the genetic differences
between asthma patients through a SARP grant.
Other SARP researchers are examining the impact of latent viral infection
and systemic inflammation on asthma.
"The overall goal is to understand the disease better so that we may be
able to target treatments to individual patients," she says.
Asthma and allergy specialist John Sweet, MD, tells WebMD that there are
promising new therapies for patients with severe, hard-to-treat asthma,
including immunosuppression aimed at calming the immune system responses that
lead to asthma, and anti-IgE, which targets allergic response.
Sweet agrees that a better understanding of the differences between asthma
patients could lead to better treatments.