Inspiratory Pulmonary Rehabilitation for Children With Obesity and Asthma

Asthma is a chronic respiratory disease affecting roughly 8% of US children, and is characterized by intermittent symptoms of breathlessness/dyspnea, chest tightness, wheeze, and cough. Although asthma is currently the most common chronic disease in childhood, there are no cures and the underlying etiologies of the various asthma phenotypes still remain unclear. More than half of the 7-8 million pediatric asthma patients in the US have one or more exacerbations each year. A sizable component of asthma's impact on children stems from the recurrent mild-moderate symptoms that cause impaired quality-of-life, activity limitation and exercise avoidance. Uncontrolled asthma frequently disrupts quality of life and is the #1 reason that children miss school and avoid physical activity. Among children with asthma, obesity is a major risk factor for disruptive asthma symptoms. Asthma is conventionally thought to stem from inflammation in the lower airways. However, despite the widespread availability of anti-inflammatory inhaled corticosteroid (ICS) drugs, uncontrolled asthma remains extremely common and appears to be less effective in obese patients. Pediatric obesity is a risk factor for both new-onset asthma and asthma that has more frequent and refractory symptoms. We found that pediatric obesity increases the risk for spirometry-confirmed asthma by nearly 30%. The mechanistic link between obesity and uncontrolled asthma remains unknown. In general, asthmatic children who are obese experience a reduced response to daily preventative ICS. Pediatric obesity has repeatedly been associated with more frequent and severe asthma symptoms, greater airflow obstruction, need for more frequent albuterol use, and more frequent and severe exacerbations. A consistent finding across most studies of children with both obesity and asthma has been an obesity-related increase in the frequency of chronic asthma symptoms (specifically dyspnea) and asthma-related activity limitation. We found that the greater asthma symptoms seen in obese versus non-obese children were primarily attributable to excess symptoms of dyspnea. Obese adolescents with asthma most commonly report that dyspnea is their most problematic asthma symptom. We hypothesize that the increased asthma symptom reporting in obese asthma, stems not from airway inflammation but rather obesity-related impaired breathing mechanics (i.e. chest restriction). Because of the reduced response to conventional asthma drugs and the resulting excess symptoms, there is a critical need for new treatment approaches for obese children with asthma that is guided by improved mechanistic understanding of this difficult phenotype.