The role of type 2 diabetes in the severity of adult asthma

Purpose of review This review summarizes recent basic, translational, and clinical research on type 2 diabetes (T2D) and its relationship with asthma severity in the context of T2D mechanisms and asthma outcomes. Recent findings Several clinical asthma outcomes, such as lung function and exacerbations, demonstrate a strong association between T2D and asthma and support that T2D contributes to worse asthma outcomes. Multiple mechanisms underlying those observed associations, and their representative biomarkers, have been proposed. However, prospective, controlled human studies in the context of both T2D and asthma are limited. Summary T2D is associated with worse asthma outcomes and more severe asthma. Yet patients with more severe or uncontrolled asthma are also at a higher risk for systemic steroid exposure, which worsens glycemic control and metabolic dysregulation. Preclinical and translational studies point to metabolic dysregulation as a driver of airway inflammation. Addressing these metabolic pathways through T2D treatment may, in turn, directly or indirectly improve clinical asthma outcomes. While additional research is needed to identify biomarkers of risk and treatment response in metabolic asthma, this review highlights the importance of considering T2D as a clinically relevant asthma comorbidity.