Asthma exacerbations are acute or subacute episodes of progressively worsening shortness of breath, cough, wheezing, and chest tightness—or some combination of these symptoms. They are characterized by decreases in expiratory airflow and objective measures of lung function, according to the National Heart, Lung, and Blood Institute’s (NHLBI) National Asthma Education and Prevention Guidelines.
Patients who have had exacerbations requiring emergency department visits, hospitalizations, or admissions to the intensive care unit have a high risk of exacerbations in the future. Accordingly, reducing the frequency of asthma exacerbations is an important goal for asthma treatment; however, the clinical features of exacerbation-prone asthma (EPA) have not been well defined.
To that end, a recent NHLBI-supported multi-center study, which included a large cohort of adults and children with severe asthma, sought to identify the clinical, physiological, inflammatory, and co-morbidity factors associated with EPA.
In this interview, James Kiley, PhD, Director of the Division of Lung Diseases at the National Heart, Lung, and Blood Institute (NHLBI), explains the purpose of the study and its potential implications for the diagnosis and treatment of individuals with EPA.
MDLinx: What was the goal of this study?
Dr. Kiley: Asthma exacerbations are a significant cause of morbidity in asthma patients, resulting in lost days from work and school, and high health care utilization. They can also contribute to progression of the disease, potentially resulting in more rapid and increased loss of lung function. The NHLBI’s Severe Asthma Research Program (SARP) is unique because it follows asthma patients, over time, thus enabling the continuous study of asthma exacerbations and how they change. The study was conducted to better understand when exacerbations occur, how they vary over time, and to characterize them within the context of patients’ overall health.
MDLinx: What was the study’s main finding?
Dr. Kiley: The study found that eosinophils, a reduced response to bronchodilators, body mass index (BMI), gastroesophageal reflux (GERD), and chronic sinusitis are all factors that are associated with a higher frequency of asthma exacerbations.
MDLinx: The researchers also sought to determine whether EPA is a distinct phenotype. What did the study conclude?
Dr. Kiley: The study suggested that EPA is a phenotype that may be distinct from severe asthma. A patient’s classification of disease severity is not necessarily associated with their exacerbation frequency. Further basic and clinical research is needed to understand the specific biology and environmental factors that contribute to exacerbation-prone phenotypes.
From the patients’ perspective, it may have implications for how individual patients are assessed and may suggest specific asthma management strategies that specifically target exacerbation frequency.
MDLinx: Given this finding, and the identification of co-morbid characteristics, could this change how asthma patients are screened and diagnosed?
Dr. Kiley: Yes. As we continue to pursue these findings and learn more about both the biology and the clinical features of EPA, it is possible that a more global, comprehensive clinical evaluation, which takes into account both a patient’s biology and overall health, will result in a better understanding of their health conditions, including EPA.
MDLinx: Could this finding mean new treatment protocols for EPA patients, or even new types of treatment?
Dr. Kiley: It is possible that a better understanding, at both the biologic and clinical level, of specific EPA phenotype(s) will translate into more integrated treatment plans for patients’ EPA as well as some other health conditions. NHLBI is uniquely positioned to pursue and advance this research by examining the history and change of patients’ asthma over time, combining biology and clinical information into a holistic view of specific asthma phenotypes. We are also positioned to enable our research communities to translate this knowledge into new diagnostic and treatment strategies for patients through programs to help support development of novel interventions, and a new clinical network that will specifically tailor potential treatments to patients’ disease phenotypes. We hope these new research efforts to tailor treatments to specific patient groups will improve disease management, and potentially prevent progression of their disease.
About Dr. Kiley: James Kiley, PhD, is Director of the NHLBI’s Division of Lung Diseases, in Bethesda, MD.