title: Exertional desaturation as a predictor of rapid lung function decline in COPD.
abstract: BACKGROUND
  To date, no clinical parameter has been associated with the decline in lung function other than emphysema severity in COPD.
  
  
  OBJECTIVE
  The main purpose of this study was to explore whether the rate of lung function decline differs between COPD patients with and without exertional desaturation.
  
  
  METHODS
  A total of 224 subjects were selected from the Korean Obstructive Lung Disease cohort. Exertional desaturation was assessed using the 6-min walk test (6MWT), and defined as a post-exercise oxygen saturation (SpO2) of < 90% or a ≥ 4% decrease. The cohort was divided into desaturator (n = 47) and non-desaturator (n = 177) groups.
  
  
  RESULTS
  There was a significant difference between the desaturator and non-desaturator groups in terms of the change in pre-bronchodilator forced expiratory volume in 1 s (FEV1) over a 3-year period of follow-up (p = 0.006). The mean rate of decline in FEV1 was greater in the desaturator group (33.8 ml/year) than in the non-desaturator group (11.6 ml/year). A statistically significant difference was also observed between the two groups in terms of the change in the St. George's Respiratory Questionnaire (SGRQ) total score over 3 years (p = 0.001).
  
  
  CONCLUSIONS
  This study suggests, for the first time, that exertional desaturation may be a predictor of rapid decline in lung function in patients with COPD. The 6MWT may be a useful test to predict a rapid lung function decline in COPD.
authors.affiliation: Department of Pulmonary and Critical Care Medicine, Hallym University Kangdong Sacred Heart Hospital, Seoul, Republic of Korea.
authors.forename: Changhwan
authors.initials: C
authors.lastname: Kim
authors.forename: Joon Beom
authors.initials: JB
authors.lastname: Seo
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Lee
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Huh
authors.forename: Jin Hwa
authors.initials: JH
authors.lastname: Lee
authors.forename: Seung Won
authors.initials: SW
authors.lastname: Ra
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: Sang-Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Sang Yeub
authors.initials: SY
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: Seung Soo
authors.initials: SS
authors.lastname: Sheen
authors.forename: Yeon-Mok
authors.initials: YM
authors.lastname: Oh
authors.forename: Yong Bum
authors.initials: YB
authors.lastname: Park
authors.forename: Sang-Do
authors.initials: SD
authors.lastname: Lee
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016138:Walking / Q000502:physiology*