Blood eosinophil count is a readily available biomarker in COPD that can assist identification of patients most likely to benefit from inhaled corticosteroids (ICS) [1]. Recent evidence has demonstrated a link between blood eosinophil count as a continuous variable and magnitude of response to ICS in terms of exacerbation rate reduction [2, 3]. The current Global Initiative for Chronic Obstructive Lung Disease (GOLD) report recommends that blood eosinophil count can be used to predict the likelihood of beneficial response to ICS, in combination with clinical assessment of exacerbation risk [1]. However, as blood eosinophil counts can show variability, particularly at higher levels [4–6], it is of clinical interest to determine how many measurements are sufficient to predict an ICS response in patients with COPD. Data from the InforMing the PAthway of COPD Treatment (IMPACT) trial showed an association between blood eosinophil count and ICS response on reduction of moderate/severe COPD exacerbations [3]. This post hoc analysis of IMPACT compared whether one or two measurements of blood eosinophil count can better predict ICS responses in patients with COPD.

血嗜酸性粒细胞计数是 COPD 中一种现成的生物标志物，可以帮助识别最有可能受益于吸入性皮质类固醇 (ICS) 的患者 [1]。最近的证据表明，血液嗜酸性粒细胞计数作为一个连续变量与对 ICS 的反应程度在恶化率降低方面存在联系 [2, 3]。目前的全球慢性阻塞性肺病倡议 (GOLD) 报告建议，血嗜酸性粒细胞计数可用于预测对 ICS 产生有益反应的可能性，并结合对恶化风险的临床评估 [1]。然而，由于血液嗜酸性粒细胞计数可能显示出变异性，特别是在较高水平时 [4-6]，因此确定多少次测量足以预测 COPD 患者的 ICS 反应具有临床意义。来自 COPD 治疗路径 (IMPACT) 试验的数据显示血嗜酸性粒细胞计数和 ICS 对减少中度/重度 COPD 恶化的反应之间存在关联 [3]。这个IMPACT的事后分析比较了血液嗜酸性粒细胞计数的一次或两次测量是否可以更好地预测 COPD 患者的 ICS 反应。