title: Oxygen desaturation in 6-min walk test is a risk factor for adverse outcomes in COPD.
abstract: The 6-min walk test (6MWT) is an exercise test that measures functional status in chronic obstructive pulmonary disease (COPD) patients and provides information on oxygen desaturation. We investigated oxygen desaturation during 6MWT as a risk factor for important COPD outcomes: mortality, frequency of exacerbations, decline in lung function and decline in lean body mass.433 COPD patients were included in the Bergen COPD Cohort Study 2006-2009, and followed-up for 3 years. Patients were characterised using spirometry, bioelectrical impedance measurements, Charlson comorbidity score, exacerbation history, smoking and arterial blood gases. 370 patients completed the 6MWT at the baseline of the study. Information on all-cause mortality was collected in 2011.Patients who experienced oxygen desaturation during the 6MWT had an approximately twofold increased risk of death (hazard ratio 2.4, 95% CI 1.2-5.1), a 50% increased risk for experiencing later COPD exacerbations (incidence rate ratio 1.6, 95% CI 1.1-2.2), double the yearly rate of decline in both forced vital capacity and forced expiratory volume in 1 s (3.2% and 1.7% versus 1.7% and 0.9%, respectively) and manifold increased yearly rate of loss of lean body mass (0.18 kg·m(-2) versus 0.03 kg·m(-2) among those who did not desaturate).Desaturating COPD patients had a significantly worse prognosis than non-desaturating COPD patients, for multiple important disease outcomes.
authors.affiliation: Centre for Clinical Research, Haukeland University Hospital, Bergen, Norway marie.waatevik@helse-bergen.no.
authors.forename: Marie
authors.initials: M
authors.lastname: Waatevik
authors.affiliation: Centre for Clinical Research, Haukeland University Hospital, Bergen, Norway.
authors.forename: Ane
authors.initials: A
authors.lastname: Johannessen
authors.affiliation: Dept of Clinical Science, University of Bergen, Bergen, Norway Dept of Gynecology and Obstetrics, Haukeland University Hospital, Bergen, Norway.
authors.forename: Francisco
authors.initials: F
authors.lastname: Gomez Real
authors.affiliation: Dept of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway.
authors.forename: Marianne
authors.initials: M
authors.lastname: Aanerud
authors.affiliation: Dept of Clinical Science, University of Bergen, Bergen, Norway.
authors.forename: Jon Andrew
authors.initials: JA
authors.lastname: Hardie
authors.affiliation: Dept of Clinical Science, University of Bergen, Bergen, Norway.
authors.forename: Per Sigvald
authors.initials: PS
authors.lastname: Bakke
authors.affiliation: Dept of Clinical Science, University of Bergen, Bergen, Norway Dept of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway.
authors.forename: Tomas Mikal
authors.initials: TM
authors.lastname: Lind Eagan
mesh_terms: D000368:Aged; D015331:Cohort Studies; D015897:Comorbidity; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009664:Norway / Q000453:epidemiology; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000401:mortality* / Q000503:physiopathology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013147:Spirometry; D014797:Vital Capacity; D000070857:Walk Test
chemical_list: D010100:Oxygen