Thomsen Laura H, Shaker Saher B, Dirksen Asger, Pedersen Jesper H, Tal-Singer Ruth, Bakke Per, Vestbo Jørgen
Department of Respiratory Medicine, Gentofte Hospital, University of Copenhagen, Denmark.
Department of Cardiothoracic Surgery, University of Copenhagen, Denmark.
Chronic Obstr Pulm Dis. 2015 May 19;2(3):204-213. doi: 10.15326/jcopdf.2.3.2014.0154.
Emphysema is an important component of COPD; however, in previous studies of the correlation between airflow limitation (AFL) and computed tomography (CT) lung density as a surrogate for emphysema has varied. We hypothesised a good correlation between lung function (forced expiratory volume in first second [FEV]) and emphysema (15 percentile density [PD15]) and that this correlation also exists between loss of lung tissue and decline in lung function even within the time frame of longitudinal studies of relatively short duration. We combined 2 large longitudinal studies (the Danish Lung Cancer Screening Trial [DLCST] and the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints [ECLIPSE]) of smokers or former smokers, with a wide range of AFL and CT lung density, and analysed data from 2148 participants who did not change smoking habits and who had at least 2 CT scans and 2 FEV measurements at least 3 years apart. Baseline correlation between FEV and PD15 was high (r=0.716, 95% confidence interval [CI]: 0.694-0.736, <0.001) indicating that at least half of the variation in FEV can be explained by variation in CT lung density. Correlation between the decline in FEV and progression of PD15 was considerably weaker (r= 0.081, 95% CI: 0.038-0.122, <0.001). Correlation is very high between lung density and lung function in a broad spectrum of smokers and ex-smokers. In contrast, the temporal associations () are weakly correlated, probably due to uncertainty in the estimation of slopes within a time frame of 3-4 years.
肺气肿是慢性阻塞性肺疾病（COPD）的一个重要组成部分；然而，在以往关于气流受限（AFL）与作为肺气肿替代指标的计算机断层扫描（CT）肺密度之间相关性的研究中，结果存在差异。我们假设肺功能（第1秒用力呼气容积[FEV]）与肺气肿（第15百分位数密度[PD15]）之间存在良好的相关性，并且即使在相对较短时间的纵向研究时间范围内，肺组织丧失与肺功能下降之间也存在这种相关性。我们将两项大型纵向研究（丹麦肺癌筛查试验[DLCST]和慢性阻塞性肺疾病纵向评估以识别预测性替代终点[ECLIPSE]）相结合，这些研究针对的是吸烟者或既往吸烟者，他们具有广泛的AFL和CT肺密度范围，并分析了2148名参与者的数据，这些参与者吸烟习惯未改变，且至少有两次间隔至少3年的CT扫描和两次FEV测量。FEV与PD15之间的基线相关性很高（r = 0.716，95%置信区间[CI]：0.694 - 0.736，<0.001），这表明FEV至少一半的变异性可由CT肺密度的变异性来解释。FEV下降与PD15进展之间的相关性明显较弱（r = 0.081，95% CI：0.038 - 0.122，<0.001）。在广泛的吸烟者和既往吸烟者中，肺密度与肺功能之间的相关性非常高。相比之下，时间关联（）相关性较弱，可能是由于在3 - 4年的时间范围内斜率估计存在不确定性。
