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Inspiratory capacity‐to‐total lung capacity ratio and dyspnoea predict exercise capacity decline in COPD
Author(s) -
Ramon Maria A.,
Ferrer Jaume,
GimenoSantos Elena,
DonaireGonzalez David,
Rodríguez Esther,
Balcells Eva,
Batlle Jordi,
Benet Marta,
Guerra Stefano,
Sauleda Jaume,
Ferrer Antoni,
Farrero Eva,
Gea Joaquim,
Barberà Joan A.,
Agustí Alvar,
RodriguezRoisin Robert,
Antó Josep M.,
GarciaAymerich Judith
Publication year - 2016
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/resp.12723
Subject(s) - medicine , copd , dynamic hyperinflation , multivariate statistics , multivariate analysis , lung volumes , bayesian multivariate linear regression , hyperinflation , diffusing capacity , cardiology , physical therapy , linear regression , lung , lung function , monetary policy , statistics , mathematics , machine learning , computer science , monetary economics , economics
Abstract 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 B org 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.