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Persistent or fixed airflow obstruction (FAO) is prevalent in up to 60% of patients with severe asthma [1] and is associated with older age, more rapid decline in lung function and increased symptoms [1–3]. The underlying mechanisms of FAO in asthma are unknown, but growing evidence suggests that parenchymal changes resulting in loss of elastic recoil and decreased lung stiffness (i.e. increased lung compliance) contribute to FAO [2, 4]. In a recent study of older asthma patients with FAO, decreased lung stiffness was the sole predictor of more severe airflow obstruction, as measured by reduced forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio [2]., Higher body mass index (BMI) is associated with less severe airway obstruction in older asthma patients with fixed airflow obstruction. This is potentially mediated through BMI-related mechanisms that increase lung stiffness (i.e. reduce lung compliance). https://bit.ly/3jBwCNy

Eosinophils are increasingly being recognised as an important characteristic feature of COPD. Patients with COPD and eosinophilic inflammation tend to respond to steroid therapy; however, many questions remain regarding the optimum measurement. Eosinophilic inflammation may be defined based on various sampling techniques, including eosinophil levels in blood, sputum, bronchoalveolar lavage or biopsy, which leads to inconsistencies in its definition. Blood eosinophils may increase in conjunction with sputum eosinophils during COPD exacerbations and therefore may be a good surrogate marker of airway eosinophilic inflammation. However, the timing of the blood eosinophil measurement, the stability of the eosinophil count and the threshold used in different studies are variable. The use of blood eosinophil count to direct biological therapies in COPD has also had variable outcomes. Eosinophilic inflammation has an important role in COPD management; however, its use as the optimum biomarker still needs further investigation. Key points Eosinophilia may play a significant role in the pathogenesis of COPD. Eosinophilic inflammation in COPD can be steroid responsive; however, eosinophilic inflammation is variable, and caution needs to be taken with measurements and the thresholds used. The long-term effects of reducing eosinophil levels in COPD is unclear. Educational aims To explore current knowledge of eosinophils in COPD. To explore the relationship between eosinophilia and corticosteroid use. To understand the limitations of assessing and using eosinophilia in COPD., Eosinophilia is common in COPD and has utility in predicting responses to inhaled or oral corticosteroids, but has limitations as a biomarker http://bit.ly/2lQcMpy

Loss of lung elastic recoil is associated with increased ventilation heterogeneity in diffusion-dependent airways in older nonsmokers with asthma and fixed airflow obstructionhttp://ow.ly/g2Sk30nbVXv