Abstract：
BACKGROUND: The European Respiratory Society (ERS) and the American Thoracic Society (ATS) recommend using z-scores, and the ATS has recommended using Global Lung Initiative (GLI)- \"Global\" race-neutral reference equations for spirometry interpretation. However, these recommendations have been variably implemented and the impact has not been widely assessed, both in clinical and research settings.
OBJECTIVE: We evaluated the ERS/ATS airflow obstruction severity classification.
METHODS: In the COPDGene Study (n = 10,108), airflow obstruction has been defined as a forced expiratory volume in one second to forced vital capacity (FEV1/FVC) ratio <0.70, with spirometry severity graded from class 1 to 4 based on race-specific percent predicted (pp) FEV1 cut-points as recommended by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). We compared the GOLD approach, using NHANES III race-specific equations, to the application of GLI-Global equations using the ERS/ATS definition of airflow obstruction as FEV1/FVC ratio < lower limit of normal (LLN) and z-FEV1 cut-points of -1.645, -2.5, and -4 (\"zGLI Global\"). We tested the four-tier severity scheme for association with COPD outcomes.
RESULTS: The lowest agreement between ERS/ATS with zGLI Global and the GOLD classification was observed in individuals with milder disease (56.9% and 42.5% in GOLD 1 and 2) and race was a major determinant of redistribution. After adjustment for relevant covariates, zGLI Global distinguished all-cause mortality risk between normal spirometry and the first grade of COPD (Hazard Ratio 1.23, 95% CI 1.04-1.44, p=0.014), and showed a linear increase in exacerbation rates with increasing disease severity, in comparison to GOLD.
CONCLUSIONS: The zGLI Global severity classification outperformed GOLD in the discrimination of survival, exacerbations, and imaging characteristics.
OBJECTIVE: We evaluated the ERS/ATS airflow obstruction severity classification.
METHODS: In the COPDGene Study (n = 10,108), airflow obstruction has been defined as a forced expiratory volume in one second to forced vital capacity (FEV1/FVC) ratio <0.70, with spirometry severity graded from class 1 to 4 based on race-specific percent predicted (pp) FEV1 cut-points as recommended by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). We compared the GOLD approach, using NHANES III race-specific equations, to the application of GLI-Global equations using the ERS/ATS definition of airflow obstruction as FEV1/FVC ratio < lower limit of normal (LLN) and z-FEV1 cut-points of -1.645, -2.5, and -4 (\"zGLI Global\"). We tested the four-tier severity scheme for association with COPD outcomes.
RESULTS: The lowest agreement between ERS/ATS with zGLI Global and the GOLD classification was observed in individuals with milder disease (56.9% and 42.5% in GOLD 1 and 2) and race was a major determinant of redistribution. After adjustment for relevant covariates, zGLI Global distinguished all-cause mortality risk between normal spirometry and the first grade of COPD (Hazard Ratio 1.23, 95% CI 1.04-1.44, p=0.014), and showed a linear increase in exacerbation rates with increasing disease severity, in comparison to GOLD.
CONCLUSIONS: The zGLI Global severity classification outperformed GOLD in the discrimination of survival, exacerbations, and imaging characteristics.
摘要：
背景：欧洲呼吸学会（ERS）和美国胸科学会（ATS）建议使用z评分，ATS建议使用全球肺倡议（GLI）-“全球”种族中性参考方程进行肺活量测定解释。然而,这些建议得到了不同的实施，影响没有得到广泛评估，在临床和研究环境中。
目的：我们评估了ERS/ATS气流阻塞严重程度分类。
方法：在COPD基因研究中（n=10,108），气流阻塞被定义为一秒钟内的用力呼气量与用力肺活量（FEV1/FVC）之比<0.70，肺活量测定严重程度根据种族特定百分比预测（pp）FEV1切点从1级到4级，如全球慢性阻塞性肺疾病倡议（GOLD）所建议的那样。我们比较了黄金方法，使用NHANESIII种族特定方程，使用ERS/ATS定义的气流阻塞的GLI-Global方程的应用，因为FEV1/FVC比率<正常下限（LLN）和z-FEV1切点为-1.645、-2.5和-4（\“zGLIGlobal\”）。我们测试了四层严重程度方案与COPD结局的相关性。
结果：在患有轻度疾病的个体中观察到ERS/ATS与zGLIGlobal和GOLD分类之间的最低一致性（在GOLD1和2中分别为56.9％和42.5％），种族是重新分配的主要决定因素。在调整相关协变量后，zGLIGlobal区分了正常肺活量测定和一级COPD之间的全因死亡风险(危险比1.23,95%CI1.04-1.44,p=0.014),并显示恶化率随着疾病严重程度的增加而线性增加，与黄金相比。
结论：zGLI全局严重程度分类在生存率的辨别方面优于GOLD，恶化,和成像特性。
目的：我们评估了ERS/ATS气流阻塞严重程度分类。
方法：在COPD基因研究中（n=10,108），气流阻塞被定义为一秒钟内的用力呼气量与用力肺活量（FEV1/FVC）之比<0.70，肺活量测定严重程度根据种族特定百分比预测（pp）FEV1切点从1级到4级，如全球慢性阻塞性肺疾病倡议（GOLD）所建议的那样。我们比较了黄金方法，使用NHANESIII种族特定方程，使用ERS/ATS定义的气流阻塞的GLI-Global方程的应用，因为FEV1/FVC比率<正常下限（LLN）和z-FEV1切点为-1.645、-2.5和-4（\“zGLIGlobal\”）。我们测试了四层严重程度方案与COPD结局的相关性。
结果：在患有轻度疾病的个体中观察到ERS/ATS与zGLIGlobal和GOLD分类之间的最低一致性（在GOLD1和2中分别为56.9％和42.5％），种族是重新分配的主要决定因素。在调整相关协变量后，zGLIGlobal区分了正常肺活量测定和一级COPD之间的全因死亡风险(危险比1.23,95%CI1.04-1.44,p=0.014),并显示恶化率随着疾病严重程度的增加而线性增加，与黄金相比。
结论：zGLI全局严重程度分类在生存率的辨别方面优于GOLD，恶化,和成像特性。
