title: Longitudinal lung volume changes in patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  The progression of lung hyperinflation in patients with chronic obstructive pulmonary disease (COPD) has not been studied in a long-term prospective cohort. We explored the longitudinal changes in lung volume compartments with the aim of identifying predictors of a rapid decline of the inspiratory capacity to total lung capacity ratio (IC/TLC).
  
  
  METHODS
  The study population comprised 324 patients with COPD who were recruited prospectively. Annual rates of changes in pulmonary function, including forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV), vital capacity (VC), IC, and IC/TLC, were estimated using the random coefficient models.
  
  
  RESULTS
  The mean annual rates of changes in pre- and post-bronchodilator FEV1 were -23.0 mL/year (p < 0.001) and -26.5 mL/year (p = 0.004). The mean annual rates of changes in VC, IC, TLC, and IC/TLC were -33.7 mL/year (p = 0.007), -53.9 mL/year (p < 0.001), -43.7 mL/year (p = 0.012), and -0.65%/year (p = 0.001), respectively. RV, FRC, and RV/TLC did not change significantly during the study period. Multivariate logistic regression analysis showed that a high modified Medical Research Council (MMRC) dyspnea scale score, a high Charlson comorbidity index value, and low post-bronchodilator FEV1 were associated with rapid decline in IC/TLC.
  
  
  CONCLUSIONS
  MMRC dyspnea scale, post-bronchodilator FEV1, and the Charlson comorbidity index at baseline were independent predictors of a rapid decline in IC/TLC.
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Olympic-ro 43 gil, Sonpa-gu, Seoul, 138-736, South Korea.
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Lee
authors.forename: Seon Ok
authors.initials: SO
authors.lastname: Kim
authors.forename: Joon Beom
authors.initials: JB
authors.lastname: Seo
authors.forename: Ji-Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Kim
authors.forename: Tae-Hyung
authors.initials: TH
authors.lastname: Kim
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Kim
authors.forename: Jin Hwa
authors.initials: JH
authors.lastname: Lee
authors.forename: Sang-Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Sangyeub
authors.initials: S
authors.lastname: Lee
authors.forename: Seong Yong
authors.initials: SY
authors.lastname: Lim
authors.forename: Tae Rim
authors.initials: TR
authors.lastname: Shin
authors.forename: Ho Il
authors.initials: HI
authors.lastname: Yoon
authors.forename: Sei Won
authors.initials: SW
authors.lastname: Lee
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Huh
authors.forename: Yeon-Mok
authors.initials: YM
authors.lastname: Oh
authors.forename: Sang-Do
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000368:Aged; D018450:Disease Progression; D004417:Dyspnea / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D005652:Functional Residual Capacity; D006801:Humans; D007320:Inspiratory Capacity; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology*; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology*; D056910:Republic of Korea; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014109:Total Lung Capacity; D014797:Vital Capacity