Dataset Information

Comparison of the variability of the annual rates of change in FEV? determined from serial measurements of the pre- versus post-bronchodilator FEV? over 5 years in mild to moderate COPD: results of the lung health study.

ABSTRACT:

Background

The impact of interventions on the progressive course of COPD is currently assessed by the slope of the annual decline in FEV? determined from serial measurements of the post-, in preference to the pre-, bronchodilator FEV?. We therefore compared the yearly slope and the variability of the slope of the pre- versus the post-bronchodilator FEV? in men and women with mild to moderate COPD who participated in the 5-year Lung Health Study (LHS).

Methods

Data were analyzed from 4484 of the 5887 LHS participants who had measurements of pre- and post-bronchodilator FEV? at baseline (screening visit 2) and all five annual visits. The annual rate of decline in FEV? (±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 FEV? 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.

Results

Within each intervention group, mean adjusted and unadjusted slope estimates were slightly higher for the pre- than the post-bronchodilator FEV? (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 FEV? (range 0.05-0.11 ml/yr). Conversely, the standard deviations of the mean FEV? 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 FEV?. 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 FEV?. 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.

Conclusion

Serial measurements of the pre-bronchodilator FEV? are generally sufficient for comparing the impact of different interventions on the annual rate of change in FEV?.

SUBMITTER: Tashkin DP

PROVIDER: S-EPMC3439318 | biostudies-literature | 2012 Aug

REPOSITORIES: biostudies-literature

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Publications

Comparison of the variability of the annual rates of change in FEV₁ determined from serial measurements of the pre- versus post-bronchodilator FEV₁ over 5 years in mild to moderate COPD: results of the lung health study.

Tashkin Donald P DP Wang He-Jing HJ Halpin David D Kleerup Eric C EC Connett John J Li Ning N Elashoff Robert R

Respiratory research 20120815

<h4>Background</h4>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).<h4>Methods</h4>Data were analyzed fr ...[more]

PMID: 22894725

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