Inspiratory capacity-to-total lung capacity ratio and dyspnoea predict exercise capacity decline in COPD

Maria A. Ramon, Jaume Ferrer, Elena Gimeno-Santos, David Donaire-Gonzalez, Esther Rodríguez, Eva Balcells, Jordi De Batlle, Marta Benet, Stefano Guerra, Jaume Sauleda, Antoni Ferrer, Eva Farrero, Joaquim Gea, Joan A. Barberà, Alvar Agustí, Robert Rodriguez-Roisin, Josep M. Antó, Judith Garcia-Aymerich

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Background and objective Exercise capacity decline is a predictor of mortality in patients with chronic obstructive pulmonary disease (COPD). Static pulmonary hyperinflation is a key determinant of exercise performance, but its effect on the longitudinal decline in exercise capacity remains unknown. We aimed to study the relationship between the inspiratory capacity-to-total lung capacity (IC/TLC) ratio and exercise capacity decline in COPD. Methods We measured IC/TLC and other relevant clinical and functional variables in 342 clinically stable patients with COPD. The 6-min walk distance (6MWD) was determined at recruitment and after a mean ± SD of 1.7 ± 0.3 years. The annual rate of change in 6MWD was calculated. Multiple imputation to account for losses during follow up was implemented, and multivariate regression was used to analyze predictive factors of 6MWD decline. Results Mean decline rate in the 6MWD was 21.9 ± 34.1 m/year. In the bivariate analysis, patients with lower levels of IC/TLC had greater 6MWD decline (-27.4 ± 42.5, -24.9 ± 36.5 and -13.4 ± 39.9 m/year in the first, second and third tertile of IC/TLC, respectively; P-for-trend = 0.018). From other potential risk factors considered, dyspnoea, health status, serum C-reactive protein and Borg dyspnoea score at the end of the exercise test were related to exercise capacity decline. In the multivariate regression model, only IC/TLC (β = 0.7 m/year per each percentage unit of IC/TLC; P = 0.007) and dyspnoea (mMRC ≥ 2) (β = -14.6 m/year; P = 0.013) were associated with the annual rate of 6MWD change. Conclusion IC/TLC and dyspnoea in clinically stable patients with COPD predict their exercise capacity decline and may help to guide early therapeutic interventions.

Original languageEnglish (US)
Pages (from-to)476-482
Number of pages7
Issue number3
StatePublished - Apr 1 2016


  • 6-min walk distance
  • Chronic obstructive pulmonary disease
  • Cohort study
  • Disease progression
  • Exercise capacity

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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