Thomason M J, Strachan D P
Department of Public Health Sciences, St George's Hospital Medical School, London SW17 0RE, UK.
Thorax. 2000 Sep;55(9):785-8. doi: 10.1136/thorax.55.9.785.
Previous epidemiological studies have related mortality from chronic obstructive pulmonary disease (COPD) to forced expiratory volumes (FEV(1) or FEV(0.75)) and it is unknown whether other spirometric indices might have greater predictive power.
A case-control study of fatal COPD was conducted within a cohort of London civil servants who performed forced expiratory spirograms in 1967-9 and were followed up for mortality over 20 years. The spirograms of 143 men who died of COPD (ICD8 491, 492 or 519.8) were compared with those of 143 controls individually matched for age, height, and smoking habit who survived longer than their matched case. Flow rates in different parts of the spirogram were compared within case-control pairs and analysed as predictors of fatal COPD by conditional logistic regression.
Within pair case:control ratios of FEV(1), mid expiratory flow rates (e.g. FEF(50-75)) and FEF(75-85) were highly intercorrelated (r>0.7) but correlations with FEF(85-95) were weaker (r<0.5). All indices except the FEV(1)/FVC ratio were stronger predictors of death from COPD within the first 10 years than of later deaths (15-19 years). After adjustment for FEV(1), mid expiratory flow rates independently predicted fatal COPD but end expiratory flow rates did not. The FEV(1) adjusted mortality ratios associated with a 10% decrement in each index were 2.24 (95% CI 1.54 to 3.76) for FEF(50-75), 1.20 (95% CI 1.00 to 1.42) for FEF(75-85), and 1.10 (95% CI 0.96 to 1.26) for FEF(85-95).
This study confirms FEV(1) and mid expiratory flow rates as powerful predictors of mortality from COPD, and suggests that measurement of end expiratory flow rates would add little extra predictive information.
既往流行病学研究已将慢性阻塞性肺疾病（COPD）死亡率与用力呼气量（FEV(1)或FEV(0.75)）相关联，而其他肺量计指标是否具有更强的预测能力尚不清楚。
在一组伦敦公务员队列中开展了一项关于致命性COPD的病例对照研究，这些公务员在1967 - 1969年进行了用力呼气肺量图检测，并随访了20多年的死亡率。将143例死于COPD（国际疾病分类第八版编码491、492或519.8）的男性的肺量图与143名年龄、身高和吸烟习惯相匹配且存活时间长于其匹配病例的对照个体的肺量图进行比较。在病例对照对中比较肺量图不同部分的流速，并通过条件逻辑回归分析作为致命性COPD的预测指标。
在配对中，FEV(1)、呼气中期流速（如FEF(50 - 75)）和FEF(75 - 85)的病例与对照比值高度相关（r>0.7），但与FEF(85 - 95)的相关性较弱（r<0.5）。除FEV(1)/FVC比值外，所有指标在最初10年内比后期死亡（15 - 19年）更能预测COPD死亡。在调整FEV(1)后，呼气中期流速可独立预测致命性COPD，但呼气末流速不能。与每个指标降低10%相关的FEV(1)调整后死亡率比值，FEF(50 - 75)为2.24（95%可信区间为1.54至3.76），FEF(75 - 85)为1.20（95%可信区间为1.00至1.42），FEF(85 - 95)为1.10（95%可信区间为0.96至1.26）。
本研究证实FEV(1)和呼气中期流速是COPD死亡率的有力预测指标，并表明测量呼气末流速几乎不会增加额外的预测信息。
