1 Intermountain Medical Center, Murray, Utah; and.
2 University of Utah, Salt Lake City, Utah.
Ann Am Thorac Soc. 2018 Aug;15(8):920-925. doi: 10.1513/AnnalsATS.201802-104OC.
Current guidelines recommend using forced expiratory volume in 1 second (FEV) % predicted to categorize the severity of airflow obstruction. There are limitations to using FEV % predicted for this purpose, including bias associated with demographic factors and the inability to correct for "lung size." Other methods for grading the severity of airflow obstruction have been proposed to address these limitations.
Our objectives were to categorize airflow obstruction severity using these methods and then determine which method results in a categorization most closely associated with mortality.
Study subjects were patients aged 40-80 years tested in our pulmonary function test laboratories in the period 2002 to 2013 with airflow obstruction based on an FEV/forced vital capacity (FVC) less than the lower limit of normal. Categorization of airflow obstruction severity was determined using four methods: FEV % predicted; FEV % predicted adjusted by FVC % predicted; FEV/FVC confidence interval approach; and FEV z-scores. Receiver operating characteristic curve analysis was used to determine which categorization method best predicts 5-year survival.
We identified 2,000 patients with airflow obstruction. Important differences in the categorization of airflow obstruction severity were observed using the different methods. More patients were categorized as having severe obstruction using FEV % predicted and FEV z-scores compared with FEV % predicted adjusted by FVC % predicted and FEV/FVC confidence interval approach. FEV % predicted was the best predictor of 5-year survival among the four methods studied.
In our study, categorizing airflow obstruction severity using FEV % predicted best predicted 5-year survival. This validates the current guideline recommendation that FEV % predicted be used to categorize the severity of airflow obstruction.
目前的指南建议使用 1 秒用力呼气量（FEV）占预计值的百分比来对气流阻塞的严重程度进行分类。但在实际应用中，使用 FEV 占预计值的百分比存在局限性，包括与人口统计学因素相关的偏差，以及无法纠正“肺容量”。为了解决这些局限性，已经提出了其他分级气流阻塞严重程度的方法。
我们的目的是使用这些方法对气流阻塞严重程度进行分类，然后确定哪种方法与死亡率的相关性最高。
研究对象为 2002 年至 2013 年间在我们的肺功能检测实验室接受检测的年龄在 40-80 岁之间的患者，这些患者存在基于 FEV/用力肺活量（FVC）低于正常值下限的气流阻塞。使用四种方法对气流阻塞严重程度进行分类：FEV 占预计值的百分比；FEV 占预计值与 FVC 占预计值之比校正后的 FEV 占预计值百分比；FEV/FVC 置信区间法；以及 FEV z 评分。使用受试者工作特征曲线分析确定哪种分类方法最能预测 5 年生存率。
我们确定了 2000 例气流阻塞患者。使用不同方法观察到气流阻塞严重程度的分类存在重要差异。与 FEV 占预计值与 FVC 占预计值之比校正后的 FEV 占预计值百分比和 FEV/FVC 置信区间法相比，使用 FEV 占预计值和 FEV z 评分的患者中更多的患者被归类为严重阻塞。在我们的研究中，四种方法中，FEV 占预计值是预测 5 年生存率的最佳指标。
在我们的研究中，使用 FEV 占预计值对气流阻塞严重程度进行分类最能预测 5 年生存率。这验证了目前的指南建议，即使用 FEV 占预计值对气流阻塞的严重程度进行分类。
