Vol. 21 • Issue 4 • Page 10
State of the Profession: ASTHMA
The prevalence of asthma has been increasing since the early 1980s across all ages, sex, and racial groups, with an estimated 20 million Americans suffering from asthma. Asthma remains one of the most common chronic diseases of childhood, affecting more than six million children.1
Internationally, it is estimated that the number of people with asthma will grow by more than 100 million by 2025.2 The drastic increase in prevalence will pull on limited resources for medical management and attempts to achieve control of asthma with proper treatment.
In the United States, asthma costs an estimated $3,300 per person in medical expenses, missed school and work days, and premature deaths between 2002 and 2007. The overall cost to treat asthma in the United States was estimated at $56 billion in 2007, a six percent increase from 2002.1
Patients with asthma continue to experience persistent disease-related symptoms and morbidity, despite access to an array of medications to optimize asthma control. The goal of chronic asthma management is intended to reduce symptoms and acute flares, and utilization of healthcare services and individualized care for the patient remains at the center for asthma care.3
However, health systems are challenged to find the time and resources to effectively respond to the impact of asthma.4 To combat the rising cost of healthcare, non-pharmacologic approaches have been emphasized equally with emerging pharmacological therapies. It has been “demonstrated that asthma morbidity can be reduced by a self-management program including self-monitoring, a written action plan, regular medical review, and asthma education.”5
Therapies
Pharmacotherapy remains the mainstay of asthma treatment. Management is based primarily on guideline recommendations, which provide a framework, but gaps in diagnosis and treatment remain, opening a window into the framework to improve care.
At the core of personalized asthma care is symptom control with pharmacologic therapy and diagnostics. The goal of personalized care is focused on decreasing morbidity, improving quality of life, and decreasing health care costs for both the patient and the provider. In most clinical settings, “asthma medications are imperfectly used by both clinicians and patients alike, resulting in needless excess morbidity and cost.”6
Ongoing advances to effectively manage asthma include the recognition of asthma as a heterogeneous disease. Recognition of phenotypes has assisted with the incorporation of medications and doses needed to achieve disease control.7 However, asthma is a complex disease process, and while the goal is to provide individualized treatment, there are both intrinsic and extrinsic factors that complicate the specific treatments directed toward biological phenotypes.
At this time, while there is a fundamental role for phenotyping (clinical, physiological, and biochemical/molecular), the matter of how to properly manage patients with severe asthma still remains.8 The process of phenotyping, much like the management of asthma, is very complex, and there is no set of predictive phenotypes to be used universally by clinicians.
The evolution of the use of phenotyping in the clinical setting is slowly bridging the gap for patients with poor asthma control, frequent exacerbations, and severe asthma, despite high-intensity treatment. Genomics is leading the revolution of personalized medicine, but the number of genes identified for the various asthma response phenotypes remains small. Increasing the number of identified genes and the functional effects will “increase the ability to predict drug treatment response.”6
The development and use of monoclonal antibodies in the clinical setting has shown positive effects for the treatment for moderate-to-severe asthma and some early potential in preventing asthma exacerbations.5 Omalizumab, a monoclonal anti-IgE antibody, is the first approved treatment of what hopefully will be many more biological targeted asthma drugs in the future. The use of omalizumab is effective in reducing symptoms when given in addition to inhaled corticosteroids and combination steroid therapy for patients who fail on maximal therapy. The treatment results in a reduction in high-affinity IgE receptors, and reduced mast cell degranulation.5
TNF-a inhibitors (cytokine tumor necrosis factor) are being studied for their role in augmenting the inflammatory response in patients with asthma. TNF-a exerts a direct bronchoconstrictor effect on smooth muscle, adding to the inflammatory process.8 Other cytokines are being targeted for their role in IgE production and implication for increased severity of asthma and exacerbations. Trials have been encouraging, but omalizumab is the only approved medication commercially available.
Pharmacotherapy remains the backbone of asthma treatment, but bronchial thermoplasty emerged over the past five years as an alternative treatment for managing severe asthma for patients who are unresponsive to conventional treatment. This alternative treatment reduces airway smooth muscle by ablating the central airways with radiofrequency energy during bronchoscopy.5 However, there has been little evidence to support thermoplasty as having any effect on airway hyperresponsiveness. Overall, patients who undergo the procedure report higher quality of life in respect to asthma control, but there is no evidence or studies evaluating the histological or morphological changes in the airway following bronchial thermoplasty.9 Because of the many phenotypes now identified as associated with asthma, phenotypic targeting will be essential for this very invasive procedure.9
Looking Forward
There are many gaps still to be filled in the management of asthma. Goals remain the same: reducing morbidity, increasing quality of life, and reducing mortality. Over the past decade, despite the many great advances in the management of asthma, current research supports the need for individualized patient care. Genomics and advanced diagnostics such as bronchial thermoplasty reflect the development of novel therapies and approaches to optimize asthma control.
Even with advances in treatment, optimal asthma management will require multidisciplinary strategies. Success will rely on communication to facilitate patient education, providing the framework for the development of personalized plans and the continued development of novel therapies.3
References
1. Centers for Disease Control and Prevention, Vital Signs. Asthma in the U.S. 2011. Available from: www.cdc.gov/vitalsigns/Asthma/
2. World Health Organization. Global surveillance, prevention and control of chronic respiratory diseases: A comprehensive approach. 2007. Available from: www.aaaai.org/about-the-aaaai/newsroom/asthma-statistics.aspx.
3. Burkett P. Insights into the burden of asthma and advances in its treatment. The Respiratory Report. 2011;6(1):46-51.
4. Stewart M, McGhan S, Watt S, et al. Health professionals’ preparation for supporting children and parents affected by asthma and allergies. J Allergy Clin Immunol. 2011;2(5):216-23.
5. Jackson D, Sykes A, Mallia P, et al. Asthma exacerbations: Origin, effect, and prevention. J Allergy Clin Immunol.2011. 128(6):1165-74.
6. Weiss S. New approaches to personalized medicine for asthma: Where are we? J Allergy Clin Immunol.2012;129(2):327-34.
7. Busse W. Asthma diagnosis and treatment: Filling in the information gaps. J Allergy Clin Immunol. 2011; 128(4), 740-50.
8. Newman M. Phenotypes in refractory asthma. The Respiratory Report. 2011;6(1):17-25.
9. Bel E. Bronchial thermoplasty: Has the promise been met? Am J Respir Crit Care Med. 2010;181:101-5.
Jasmine Dolan, DNP, FNP-BC, AE-C, of Northern Colorado Allergy & Asthma Clinic, LLC, in Fort Collins, is a member of the Association of Asthma Educators Education Committee.
ADVANCE thanks the Association of Asthma Educators for providing this report. For more information on AAE: www.asthmaeducators.org, 800-988-7747.
