第6秒用力呼气容积替代用力肺活量诊断轻中度慢性阻塞性肺疾病价值的研究

FEV_6 as A Surrogate for FVC in the Diagnosis for Mild-Moderate Chronic Obstructive Pulmonary Disease

目的评估第6秒用力呼气容积(FEV6)替代用力肺活量(FVC)诊断轻中度慢性阻塞性肺疾病(COPD)的效果。方法对2010年1月至2012年10月河北省胸科医院402例舒张后呼气时间达6 s以上的轻中度COPD患者及217例非COPD患者的肺功能检查结果进行回顾性分析,对FEV6与FVC、FEV1/FEV6与FEV1/FVC进行相关性分析,以FEV1/FVC<70%为金标准,绘制FEV1/FEV6的受试者工作特征(ROC)曲线,确定最佳诊断界值。结果 FEV6与FVC、FEV1/FEV6与FEV1/FVC高度相关,相关系数分别为0.992和0.980。以FEV1/FEV6<70%为诊断标准,402例轻中度COPD患者的假阴性率为12.69%,假阴性患者的FEV1/FVC非常接近70%的诊断界值。FEV1/FEV6替代FEV1/FVC诊断轻中度COPD的最佳诊断界值为72%,敏感度为94.7%,特异度为92.2%。结论FEV6与FVC高度相关,尽管可能导致假阴性的出现,FEV6可以有效替代FVC用于诊断轻中度COPD,FEV1/FEV6的最佳诊断界值为72%。

Objective To determine the efficacy of forced expiratory volume in six seconds（ FEV6 ） as an alternative for forced vital capacity （FVC） in the diagnosis for mild-moderate chronic obstructive pulmonary disease（COPD）. Methods A total of 402 mild-moderate COPD and 217 non-COPD patients＇ spirometric examinations were retrospectively analyzed. The correlation between FEVs and FVC, FEV1/FVC and FEV1/FEV6 was evaluated by the Spearman test. Considering FEV1/FVC 〈 70% as being the ＇golden standard＇ for airway obstruction, a ROC curve was used to determine the best cut-off point for the FEV1/FEV6 ratio in the diagnosis for COPD. Results The Spearman correlation test revealed the FEV1 and FEV6, FEV,/FEV6 and FEV1/FVC ratios were highly correlated （r = 0. 992, 0.980, respectively, P = 0. 000）. Using FEV1/FEV6 〈 70% as the diagnosis standard, 12.69% of the 402 patients could not be diagnosed as COPD. The FEV1/FVC ratio of these patients was very close to 70%. The best cut-off point for the FEV1/FEV6 ratio in the diagnosis of mild-moderate COPD was 72% while the sensitivity and specificity were 94.7% and 92.2%, respectively. Conclusions There is a strong correlation between FEV1/FVC and FEV1/FEV6. The FEV6 can be a valid alternative for FVC in the diagnosis for mild-moderate COPD,although it may result in false negative. The best cut-off point for the FEV1/FEV6 ratio is 72%.