Departments of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
Respir Res. 2012 Aug 15;13(1):70. doi: 10.1186/1465-9921-13-70.
The impact of interventions on the progressive course of COPD is currently assessed by the slope of the annual decline in FEV₁ determined from serial measurements of the post-, in preference to the pre-, bronchodilator FEV₁. We therefore compared the yearly slope and the variability of the slope of the pre- versus the post-bronchodilator FEV₁ in men and women with mild to moderate COPD who participated in the 5-year Lung Health Study (LHS).
Data were analyzed from 4484 of the 5887 LHS participants who had measurements of pre- and post-bronchodilator FEV₁ at baseline (screening visit 2) and all five annual visits. The annual rate of decline in FEV₁ (±SE) measured pre- and post-bronchodilator from the first to the fifth annual visit was estimated separately using a random coefficient model adjusted for relevant covariates. Analyses were performed separately within each of the three randomized intervention groups. In addition, individual rates of decline in pre- and post-bronchodilator FEV₁ were also determined for each participant. Furthermore, sample sizes were estimated for determining the significance of differences in slopes of decline between different interventions using pre- versus post-bronchodilator measurements.
Within each intervention group, mean adjusted and unadjusted slope estimates were slightly higher for the pre- than the post-bronchodilator FEV₁ (range of differences 2.6-5.2 ml/yr) and the standard errors around these estimates were only minimally higher for the pre- versus the post-bronchodilator FEV₁ (range 0.05-0.11 ml/yr). Conversely, the standard deviations of the mean FEV₁ determined at each annual visit were consistently slightly higher (range of differences 0.011 to 0.035 L) for the post- compared to the pre-bronchodilator FEV₁. Within each group, the proportion of individual participants with a statistically significant slope was similar (varying by only 1.4 to 2.7%) comparing the estimates from the pre- versus the post-bronchodilator FEV₁. However, sample size estimates were slightly higher when the pre- compared to the post-bronchodilator value was used to determine the significance of specified differences in slopes between interventions.
Serial measurements of the pre-bronchodilator FEV₁ are generally sufficient for comparing the impact of different interventions on the annual rate of change in FEV₁.
目前，通过测定支气管扩张剂后用力肺活量（FEV₁）的年下降斜率来评估干预措施对 COPD 进展的影响，这一斜率优于支气管扩张剂前用力肺活量（FEV₁）。因此，我们比较了参加为期 5 年的肺健康研究（LHS）的轻度至中度 COPD 男性和女性的支气管扩张剂后与支气管扩张剂前 FEV₁的年斜率和斜率变化。
对 5887 名 LHS 参与者中的 4484 名参与者进行了数据分析，这些参与者在基线（筛查访问 2）和所有 5 次年度访问时均进行了支气管扩张剂前和支气管扩张剂后 FEV₁ 的测量。使用随机系数模型分别估计从第一次年度访问到第五次年度访问时支气管扩张剂前和支气管扩张剂后 FEV₁ 的年下降率（±SE），该模型调整了相关协变量。在三个随机干预组内分别进行了分析。此外，还为每位参与者确定了支气管扩张剂前和支气管扩张剂后 FEV₁ 的个体下降率。此外，还估计了使用支气管扩张剂前和支气管扩张剂后测量来确定不同干预措施之间下降斜率差异的显著性所需的样本量。
在每个干预组内，支气管扩张剂前 FEV₁ 的平均调整和未调整斜率估计值略高于支气管扩张剂后 FEV₁（差异范围为 2.6-5.2 ml/yr），并且这些估计值的标准误差仅略高于支气管扩张剂后 FEV₁（差异范围为 0.05-0.11 ml/yr）。相反，在每次年度访问时确定的平均 FEV₁ 的标准差始终略高（差异范围为 0.011 至 0.035 L），支气管扩张剂后 FEV₁ 高于支气管扩张剂前 FEV₁。在每个组内，使用支气管扩张剂前和支气管扩张剂后 FEV₁ 进行估计时，具有统计学显著斜率的个体参与者的比例相似（仅相差 1.4%至 2.7%）。然而，当使用支气管扩张剂前 FEV₁ 值来确定干预措施之间特定斜率差异的显著性时，样本量估计值略高。
支气管扩张剂前 FEV₁ 的连续测量通常足以比较不同干预措施对 FEV₁ 年变化率的影响。
