Purpose: Eosinophil count elevations are predictive of adverse outcomes in patients with asthma, yet little is known regarding longitudinal eosinophil patterns and their association with clinical outcomes. The goal of this study was to assess associations between longitudinal persistence of eosinophil elevations and both clinical outcomes and health care resource utilization (HCRU).
Methods: Data were extracted from 2 databases in the United Kingdom. Patients included were aged ≥ 13 years, had active asthma, and had ≥ 3 blood eosinophil count (BEC) recordings. Patients were categorized by BEC as: never high (all BEC ≤ 300 cells/μL), intermittently high (≥ 1 BEC > 300 cells/μL but < 75% of BEC > 300 cells/μL), or persistently high (≥ 75% of BEC > 300 cells/μL). Asthma exacerbations, asthma control (risk domain, overall, and full), and HCRU were evaluated for 12 months after the last BEC.
Results: The study population comprised 148,021 patients. Persistently high, intermittently high, and never high eosinophil patterns were detected in 13.6%, 40.5%, and 45.9% of patients, respectively. Patients with ≥ 1 elevated BEC were at greater risk for severe asthma exacerbations, regardless of whether the elevation was persistent (rate ratio [RR]: 1.28 [95% CI 1.24– 1.33]; P < 0.001) or intermittent (RR: 1.24 [95% CI 1.21– 1.27]; P < 0.001), compared with patients with no eosinophil elevations. Full asthma control was achieved by < 25% of patients across eosinophil pattern groups, and HCRU did not appreciably differ, although patients with persistently high BEC had the shortest hospital stay duration among the groups.
Conclusion: These data suggest that elevated blood eosinophils, regardless of persistency, signify increased risk of severe asthma exacerbations.

Keywords: asthma control, asthma exacerbation, biomarker, eosinophilia, phenotype, type 2 inflammation


中文翻译：

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嗜酸性哮喘内型和临床结果的持续性：真实世界的观察性研究

目的：嗜酸性粒细胞计数升高可预测哮喘患者的不良结局，但对纵向嗜酸性粒细胞模式及其与临床结局的关联知之甚少。本研究的目的是评估嗜酸性粒细胞升高的纵向持续性与临床结果和医疗资源利用 (HCRU) 之间的关联。
方法：数据来自英国的 2 个数据库。纳入的患者年龄 ≥ 13 岁，患有活动性哮喘，并且有 ≥ 3 次血液嗜酸性粒细胞计数 (BEC) 记录。患者按 BEC 分类为：从不高（所有 BEC ≤ 300 细胞/μL）、间歇性高（≥ 1 BEC > 300 细胞/μL 但 < 75% 的 BEC > 300 细胞/μL）或持续高（≥ 75% BEC > 300 个细胞/μL）。在最后一次 BEC 后 12 个月内评估了哮喘发作、哮喘控制（风险域、总体和全面）和 HCRU。
结果：研究人群包括 148,021 名患者。分别有 13.6%、40.5% 和 45.9% 的患者检测到持续高、间歇高和从不高的嗜酸性粒细胞模式。BEC 升高≥ 1 的患者发生严重哮喘发作的风险更大，无论升高是持续性的（比率 [RR]：1.28 [95% CI 1.24-1.33]；P < 0.001）还是间歇性的（RR：1.24 [ 95% CI 1.21–1.27]；P < 0.001)，与没有嗜酸性粒细胞升高的患者相比。在嗜酸性粒细胞模式组中，<25% 的患者实现了哮喘完全控制，并且 HCRU 没有明显差异，尽管持续高 BEC 的患者在各组中住院时间最短。
结论：这些数据表明，无论持续性如何，血液嗜酸性粒细胞升高都意味着哮喘严重恶化的风险增加。

关键词：哮喘控制，哮喘发作，生物标志物，嗜酸性粒细胞增多，表型，2型炎症