Format

Send to

Choose Destination
Respir Med. 2015 Aug;109(8):1058-62. doi: 10.1016/j.rmed.2015.06.012. Epub 2015 Jun 24.

The effect of bronchodilators on forced vital capacity measurement in patients with idiopathic pulmonary fibrosis.

Author information

1
Department of Medicine, University of California San Francisco, San Francisco, CA, United States. Electronic address: Deborah.Assayag@mail.mcgill.ca.
2
Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, United States.
3
Department of Medicine, University of British Columbia, Vancouver, Canada.
4
School of Medicine, University of Modena, Modena, Italy.
5
Division of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, United States.
6
Department of Radiology, University of California San Francisco, San Francisco, CA, United States.
7
Department of Medicine, University of California San Francisco, San Francisco, CA, United States.
8
Department of Pathology, University of California San Francisco, San Francisco, CA, United States.

Abstract

BACKGROUND:

Forced vital capacity (FVC) is a key measure of disease severity in patients with idiopathic pulmonary fibrosis (IPF) and is an important clinical trial endpoint. We hypothesize that reversible airflow limitation co-exists in a subgroup of patients with IPF, and that bronchodilator use will improve the performance characteristics of FVC.

METHODS:

IPF patients with pre and post-bronchodilator spirometry testing performed were identified from two tertiary referral cohorts. The difference between pre and post-bronchodilator FVC (intra-test difference) was calculated. The test characteristics of pre and post-bronchodilator FVC change over time (inter-test difference) were assessed in patients with sequential spirometry, and were used to generate sample size estimates for hypothetical clinical trials using change in FVC as the primary endpoint.

RESULTS:

There were 551 patients, contributing 967 unique spirometry tests. The mean intra-test increase in FVC with bronchodilator use was 0.04 L (2.71 vs. 2.75 L, p < 0.001). Reversible airflow limitation (increase in FEV1 or FVC of ≥12% and ≥200 mL) occurred in 9.1% of patients. The inter-test difference in change in FVC over time were equivalent for pre and post-bronchodilator (p = 0.65), leading to similar sample size estimates in a hypothetical clinical trial using change in FVC as the primary endpoint.

CONCLUSION:

Approximately one in ten patients with IPF has physiological evidence of reversible airflow limitation, and bronchodilator use in these patients may improve the assessment of disease progression based on FVC change over time. Bronchodilator use does not appear to meaningfully impact the precision of FVC as an endpoint in clinical trials.

KEYWORDS:

Bronchodilators; Clinical trials; Idiopathic pulmonary fibrosis; Lung function; Spirometry

PMID:
26140806
PMCID:
PMC4522344
DOI:
10.1016/j.rmed.2015.06.012
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center