Vol. 18 •Issue 6 • Page 37
More Asthma Cases
Mean More Asthma Emergencies
Asthma in the United States has been increasing in prevalence since 1980. Officials at the Centers for Disease Control and Prevention in Atlanta report that in 2000, asthma was responsible for 4,487 deaths nationwide. In addition, there were an estimated 465,000 hospitalizations, 1.8 million emergency department (ED) visits and 10.4 million physician office visits.1
When a patient presents in the emergency room, we therapists swing into high gear. Patients instantly get nebulizers and oxygen and are put on a pulse ox. But what tools can we employ before they get to the ER? Is it possible that we can control their asthma and stop the exacerbation from happening to begin with?
Recent reports suggest that more than half of the 20 million Americans with asthma have an allergic form of the disease. For these patients, their condition is aggravated by exposure to allergens like pollen, dust mites and mold. These data coupled with reports that approximately half of all asthmatics are poorly controlled have kicked researchers into overdrive.
At the upcoming AAAA&I conference in San Antonio on March 18-22, there will be several poster and abstract sessions relating to new ways to control the allergic component of asthma.
One of the more interesting studies being presented looks at the pharmacoeconomics of allergen immunotherapy (IT) in patients with allergic rhinitis and asthma. Italian researchers wanted to know whether using IT had an economic advantage over standard anti-allergy therapy. They enrolled 30 patients with pollen-induced rhinitis and asthma. Twenty were treated with subcutaneous IT in the traditional 12-week regimen used by most allergists, and 10 were treated with regular anti-allergy medications.
Six-Year Study
Researchers followed these patients for six years and found the follow-on costs associated with the IT therapy patients were 15 percent less after one year, 48 percent less after three years, and 80 percent less after six years when compared to the costs of treating the other patients.2
Another Italian study looked at whether allergic rhinitis precipitated the development of asthma. In that instance, researchers followed 436 non-asthmatics in 1990 and 1991. They monitored the patients again in 2000 and found individuals with a diagnosis of allergic rhinitis as far back as the early 90s were more likely to have an asthma diagnosis by the year 2000.3
These data, though preliminary, seem to suggest that controlling rhinitis and inflammation is important. But what tools do we have at our disposal to do so? Corticosteroids are the traditional weapons of choice.
There are several new studies coming out looking at the efficacy of omalizumab (Xolair®) therapy. Omalizumab is a monoclonal anti-IgE antibody that binds free human IgE with a binding affinity higher than that observed between IgE and Fc-epsilon-RI.
Basically, this means it stops IgE-mediated responses without causing basophil degranulation. A combined British and American study pooled data from seven studies involving a total of 4,308 patients and deduced that omalizumab significantly reduces emergency visits in patients with severe persistent asthma when the drug is added to their traditional therapy.4
Meanwhile, an American Phase II trial of daclizumab (Zenapax®) showed the drug blocked the secretion of pro-inflammatory cytokines: TNF-a, IFN-a, IL-6, and TNF-a; but it did not did not significantly inhibit T cell proliferation. Daclizumab is a humanized monoclonal antibody believed to be directed against IL-2 receptors.
While these data doesn’t really help today’s asthmatics, they may help researchers understand how to control inflammation.5
Plasmid Injection Research
Other researchers are delving into using plasmid DNA injections to control the allergic responses to cockroaches in mice.6 While it will be a long time before these injections are translated into human testing, the studies may point the way to a better understanding of the inflammatory process. Cockroach allergens have been well documented as an asthma trigger in children.
Tools we use to manage asthma have improved dramatically over the years. As our understanding of the disease process progresses, so will medications that help us not only mange the disease, but hopefully prevent it.
Reference
1. CDC, National Center for Health Statistics. Asthma prevalence, health care use and mortality, 2000-2001. Available at http://www.cdc.gov/nchs/products/pubs/pubd/hestats/asthma/asthma.htm.
2. Ariano R, Beto P, et al. Pharmacoeconomics of Allergen Immunotherapy in Allergic Rhinitis and Asthma. AAAA&I Posters and Abstracts, Presentation Number: 298.
3. Russo C, Al-Delaimy, et al. A Hospital-Based Retrospective Cohort Study of Allergen Immunotherapy as a Preventive Treatment for New Onset Asthma. AAAA&I Posters and Abstracts, Presentation Number: 302.
4. Korenblat P, Meltzer E, Busse W, Hedgecock S, Fox H, Blogg M. Omalizumab, an Anti-IgE Antibody, Significantly Reduces Emergency Visits in Patients with Severe Persistent Asthma: A Pooled Analysis Presentation. AAAA&I Posters and Abstracts, Number: 303.
5. Sornasse TR, Hong W, Schreck R, Zhang Y, Sheridan J, Shi J , Woo J, Tsao T, Vexler V. Daclizumab in vitro inhibits the secretion of pro-asthmatic and pro-inflammatory cytokines by activated T cells. AAAA&I Posters and Abstracts, Presentation Number: 292.
6. Zhou B, Yang J, Lee J, Hill B, Zaoping D, Kanagant S. Allergy Immune Response is Modulated by DNA Vaccination For Cockroach Allergy in Mice. AAAA&I Posters and Abstracts, Presentation Number: 533.
Margaret Clark is a Georgia practitioner.
Do you live in an Asthma Capital?
On February 16, 2005, the Asthma and Allergy Foundation of America (AAFA), a non-profit consumer and patient organization, released its annual report listing to top 100 asthma centers in America.
Cities across the country are ranked on a 12-point scale to determine which metropolitan areas are the worst for asthmatics. Specifically the cities are ranked on estimated prevalence, reported prevalence, mortality, annual pollen level, air quality, smoking laws, number of asthma specialists, school inhaler access laws, rescue medication use per patient, controller medication use per patient, uninsured rate and poverty rate.
Topping the list of the worst places in America for asthmatics this year are Knoxville, and Memphis, Tenn.; Louisville, Ky.; Toledo, Ohio; and Washington, D.C. This is Knoxville’s second year in a row at number one; but surprisingly, Washington, D.C., jumped from number 50 last year to number five on this year’s list.
You can check out how your metropolitan area measures up at www.AsthmaCapitals.com.
