Radboud university medical center, Nijmegen.
Eur Respir J. 2014 Jan;43(1):54-63. doi: 10.1183/09031936.00158212. Epub 2013 Apr 5.
The aim of this study was to establish which cut-off point for the forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio (i.e. fixed 0.70 or lower limit of normal (LLN) cut-off point) best predicts accelerated lung function decline and exacerbations in middle-aged smokers. We performed secondary analyses on the Lung Health Study dataset. 4045 smokers aged 35-60 years with mild-to-moderate obstructive pulmonary disease were subdivided into categories based on presence or absence of obstruction according to both FEV1/FVC cut-off points. Post-bronchodilator FEV1 decline served as the primary outcome to compare subjects between the categories. 583 (14.4%) subjects were nonobstructed and 3230 (79.8%) subjects were obstructed according to both FEV1/FVC cut-off points. 173 (4.3%) subjects were obstructed according to the fixed cut-off point, but not according to the LLN cut-off point ("discordant" subjects). Mean±SE post-bronchodilator FEV1 decline was 41.8±2.0 mL·year(-1) in nonobstructed subjects, 43.8±3.8 mL·year(-1) in discordant subjects and 53.5±0.9 mL·year(-1) in obstructed subjects (p<0.001). Our study showed that FEV1 decline in subjects deemed obstructed according to a fixed criterion (FEV1/FVC <0.70), but non-obstructed by a sex- and age-specific criterion (LLN) closely resembles FEV1 decline in subjects designated as non-obstructed by both criteria. Sex and age should be taken into account when assessing airflow obstruction in middle-aged smokers.
本研究旨在确定 1 秒用力呼气量（FEV1）/用力肺活量（FVC）比值的截断值（即固定 0.70 或正常下限（LLN）截断值），以最佳预测中年吸烟者的肺功能加速下降和恶化。我们对肺健康研究数据集进行了二次分析。将 4045 名年龄在 35-60 岁之间、有轻中度阻塞性肺疾病的吸烟者根据两种 FEV1/FVC 截断值是否存在阻塞进行了分类。支气管扩张剂后 FEV1 下降作为主要结局指标，用于比较各分类之间的受试者。根据两种 FEV1/FVC 截断值，583 名（14.4%）受试者无阻塞，3230 名（79.8%）受试者阻塞。173 名（4.3%）受试者根据固定截断值阻塞，但不符合 LLN 截断值（“不一致”受试者）。无阻塞受试者的支气管扩张剂后平均 FEV1 下降率为 41.8±2.0 mL·年(-1)，不一致受试者为 43.8±3.8 mL·年(-1)，阻塞受试者为 53.5±0.9 mL·年(-1)（p<0.001）。我们的研究表明，根据固定标准（FEV1/FVC<0.70）判断为阻塞的受试者的 FEV1 下降率，与根据性别和年龄特定标准（LLN）判断为非阻塞的受试者的 FEV1 下降率非常相似。在评估中年吸烟者的气流阻塞时，应考虑性别和年龄因素。
