SOURCE: Bhatt NA, Lazarus A. Obesity-related asthma in adults. Postgrad Med 2016;128:563-566.
Asthma, like hypertension, may be more than one entity. That is, more than one underlying pathophysiology may lead to similar phenotypic expression. Just as hyperaldosteronism may present with hypertension that is otherwise indistinguishable from “essential hypertension,” might the clinical presentation of asthma reflect various underpinnings?
It perhaps has been underappreciated that risk for development of asthma increases as body mass index increases over 25 kg/m2, that obese asthmatics may be more treatment resistant, and that obese asthmatics experience higher rates of asthma-related hospitalizations (with worse outcomes).
Mechanistically, obesity-related asthma (ORA) is characterized by less occurrence of atopy and eosinophilia. Perhaps this helps explain the observation that steroid responsiveness is lower in ORA patients. Other pathways of inflammation differ in ORA vs. atopic asthma, such as interleukin levels.
Determining which aberrant inflammation circuitry in ORA deserves intervention to improve ORA outcomes is not yet clear. On the other hand, there are very encouraging prospective randomized trial data confirming improvements in asthma achieved through weight loss in obese patients. Clinicians should be aware that individualization of treatment for ORA may need to include attention to weight reduction to optimize outcomes.