Email updates

Keep up to date with the latest news and content from Respiratory Research and BioMed Central.

Open Access Highly Accessed Research

Longitudinal inspiratory capacity changes in chronic obstructive pulmonary disease

Bartolome R Celli1*, Marc Decramer2, Theodore Lystig3, Steven Kesten3 and Donald P Tashkin4

Author Affiliations

1 Pulmonary Division, Brigham and Women’s Hospital, Boston, MA, USA

2 Respiratory Division, University of Leuven, Leuven, Belgium

3 Respiratory Department, Boehringer Ingelheim, Pharmaceuticals Inc, Ridgefield, Connecticut, USA

4 Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA

For all author emails, please log on.

Respiratory Research 2012, 13:66  doi:10.1186/1465-9921-13-66

Published: 6 August 2012



The changes in inspiratory capacity (IC) over time in chronic obstructive pulmonary disease (COPD) patients are unknown. The Understanding Potential Long-term Impacts on Function with Tiotropium (UPLIFT®) trial included IC measurements.


IC analysis from UPLIFT® (N = 5992) was performed at 1 and 6 months, and every 6 months through 4 years. Annualized rate of decline in pre- and post-bronchodilator IC and mean differences at each time point were analyzed by mixed-effects models. The relationships between baseline IC and exacerbation rate and mortality were explored using Cox regression analysis.


Baseline characteristics: age, 65 years; 75% men; post-bronchodilator forced expiratory volume in 1 second, 1.32 L (48% predicted); pre- and post-bronchodilator IC, 2.03 and 2.33 L. Mean IC rate of decline (mL/year) was 34 ± 2 (1.7% of baseline) and 50 ± 3 (2.1% of baseline) pre- and post-bronchodilator, respectively, without significant between-group differences. Morning pre-bronchodilator (trough) IC improved with tiotropium versus placebo: 124 mL (1 month), 103 mL (1 year), 107 mL (2 years), 98 mL (3 years), and 97 mL (4 years) (all p < 0.001). Post-bronchodilator improvements were similar between treatment groups. Lower baseline IC values were associated with reduced time to first exacerbation. For the lowest quartile (n = 1413) the values in months were 14.3 (11.7–17.0) for tiotropium and 10.3 (8.8–11.7) for controls (p < 0.01).


IC declines from approximately 34 to 50 mL/year in patients with stage II to IV COPD. Tiotropium treatment does not change the IC decline rate but provides 24-hour improvements in IC sustained over the long term. Trough IC differences suggest that tiotropium provides sustained decrease in end-expiratory lung volume.

COPD; Inspiratory Capacity; Tiotropium