title: Does the 6-minute walk test predict nocturnal oxygen desaturation in patients with moderate to severe COPD?
abstract: Patients with chronic obstructive pulmonary disease (COPD) who have nocturnal oxygen desaturation (NOD) can be treated with nocturnal oxygen therapy (NOT) to avoid possible morbidity and mortality. Although there is no definite data recommending NOT alone, our aim is to evaluate the relationship between desaturation during the six-minute walk test (6MWT) and NOD in COPD. Fifty-five stable patients with COPD were enrolled in this study. The 6MWT and nocturnal oximetry were performed. Patients with comorbid diseases and respiratory failure were excluded. In total, 55 patients (49 males and 6 females, mean age: 65.8 ± 8.4 years) were analysed. Twenty-seven of the patients had moderate COPD and the remainder (n = 28) had severe COPD. Three patients (11%) with moderate COPD and 12 patients (42.9%) with severe COPD desaturated during 6MWT (p = 0.003). NOD was observed in five patients with severe COPD (17.9%). There were no patients with NOD in the moderate COPD group. Three (25%) of patients with severe COPD who desaturated during the 6MWT also had NOD. NOD was more common in patients with severe COPD and the patients with higher carbon dioxide levels (p = 0.02 and p = 0.001). Three patients (11%) with moderate COPD desaturated during the 6MWT; however they did not have NOD. Although the sample size in this study was too small to be conclusive, NOD was more common in desaturators during the 6MWT particularly in patients with severe COPD.
authors.affiliation: Department of Pulmonology, Faculty of Medicine, Istanbul University, Istanbul, Turkey snmkaraosman@gmail.com.
authors.forename: Sinem
authors.initials: S
authors.lastname: Iliaz
authors.affiliation: Department of Pulmonology, Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Tulin
authors.initials: T
authors.lastname: Cagatay
authors.affiliation: Department of Pulmonology, Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Zuleyha
authors.initials: Z
authors.lastname: Bingol
authors.affiliation: Department of Pulmonology, Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Gulfer
authors.initials: G
authors.lastname: Okumus
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Raim
authors.initials: R
authors.lastname: Iliaz
authors.affiliation: Division of Physiotherapy and Rehabilitation, Faculty of Health Sciences, Istanbul University, Istanbul, Turkey.
authors.forename: Goksen
authors.initials: G
authors.lastname: Kuran
authors.affiliation: Department of Pulmonology, Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Esen
authors.initials: E
authors.lastname: Kiyan
authors.affiliation: Department of Biostatistics, Faculty of Medicine, Istanbul University, Istanbul, Turkey.
authors.forename: Penbe
authors.initials: P
authors.lastname: Cagatay
mesh_terms: D000368:Aged; D005080:Exercise Test; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010102:Oxygen Inhalation Therapy; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D012720:Severity of Illness Index; D012890:Sleep; D016138:Walking
keywords: COPD stage; Chronic obstructive pulmonary disease; nocturnal desaturation; nocturnal oxygen therapy; six-minute walk test