Among patients with asthma, insulin resistance (IR) is prevalent and associated with decreased lower lung function, an increased rate of lung function loss, and decreased responses to conventional treatment.
Putting It Into Practice
Obesity and metabolic syndrome are known to negatively impact patients with asthma.
As a pleiotropic hormone, insulin not only regulates glucose levels but is involved in cell growth and differentiation. Insulin also regulates metabolic processes, including glucose uptake, lipid synthesis, oxidation, and fat storage. Because there are insulin receptors in the lung, insulin has the potential to influence lung cell structure and function, and mediate disease development and progression.
Patients with asthma who are obese have improved outcomes with weight loss and correction of metabolic dysregulation.
Why this study matters
Of the components of metabolic syndrome, only IR has been shown to modify the effect of obesity on asthma. The current study showed that IR has a negative effect on lung function and the efficacy of standard asthma treatments in patients with asthma.
Even though the pathophysiologic basis for decreased lung function in patients with asthma and IR or hyperinsulinemia has not been established, treatment of IR with insulin sensitizers may not only preserve lung function long-term, but normalize the treatment response to bronchodilators and corticosteroids.
Data were obtained from the Severe Asthma Research Program 3. HOMA-IR values, and before and after treatment (inhaled albuterol and intramuscular triamcinolone acetonide) and lung function (FEV1 and FVC) values were determined yearly x 5 y.
Results and conclusion
Three hundred seven patients with asthma were studied: 170 were obese and 140 had IR.
The FEV1 and FVC were lower in patients with IR than patients without IR and independent of obesity. Furthermore, the FEV1 was lower in response to treatment in patients with IR compared to patients without IR.
The annualized decrease in FEV1 was as follows: moderate IR, -41 ml/y; severe IR, -32 ml/y; and no IR, -13 ml/y.
Peters MC, Schiebler ML, Cardet JC, et al. The impact of insulin resistance on loss of lung function and response to treatment in asthma. American Journal of Respiratory and Critical Care Medicine 2022; doi.org/10.1164/rccm.202112-2745OC .