title: Six-minute walk test closely correlates to "real-life" outdoor walking capacity and quality of life in patients with intermittent claudication.
abstract: OBJECTIVE
  We used outdoor walking distance measured during 40 minutes as "real-life" outdoor walking capacity in 49 patients with intermittent claudication (IC). The outdoor walking distance was measured by a global positioning system application for a smartphone. The relationships of self-reported maximum walking distance (SR-MWD), the MWD on a graded treadmill test, and the 6-minute maximum walk distance (6MWD) vs outdoors walking capacity were investigated. Also studied were the associations of SR-MWD, MWD, and 6MWD with health-related quality of life assessed with the disease-specific instrument the Vascular Quality of Life Questionnaire (VascuQoL).
  
  
  METHODS
  In this prospective observational cohort study, 49 IC patients underwent an outdoor walking capacity test for 40 minutes, and MWD and 6MWD were measured. SR-MWD was recorded, and all subjects completed the VascuQoL questionnaire. Associations between the different walk estimates and outdoor walking capacity and health-related quality of life were investigated by correlation analysis (Spearman ρ).
  
  
  RESULTS
  Outdoor walking distance during 40 minutes was a median 2495 m (range, 1110-3300 m). SR-MWD correlated moderately and MWD correlated strongly to outdoor walking capacity (r = 0.56 and r = 0.65; P < .001, respectively). The 6MWD test showed the largest correlation to the outdoor walking capacity (r = 0.78; P < .001). The 6MWD was the only test that showed correlations with the VascuQoL sum score (r = 0.53; P < .01) and all of the domain scores, whereas SR-MWD and MWD showed weak correlations to the VascuQoL.
  
  
  CONCLUSIONS
  The distance walked during the 6-minute walk test is closely correlated to outdoor walking capacity and health-related quality of life in IC patients. Our data support the use of 6MWD for routine clinical evaluation of walking capacity in IC patients.
authors.affiliation: Department of Vascular Surgery and Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital and Academy, Gothenburg, Sweden. Electronic address: joakim.nordanstig@vgregion.se.
authors.forename: Joakim
authors.initials: J
authors.lastname: Nordanstig
authors.affiliation: Department of Vascular Surgery and Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital and Academy, Gothenburg, Sweden.
authors.forename: Monica
authors.initials: M
authors.lastname: Broeren
authors.affiliation: Department of Vascular Surgery and Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital and Academy, Gothenburg, Sweden.
authors.forename: Marlene
authors.initials: M
authors.lastname: Hensäter
authors.affiliation: Department of Vascular Surgery and Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital and Academy, Gothenburg, Sweden.
authors.forename: Angelica
authors.initials: A
authors.lastname: Perlander
authors.affiliation: Department of Vascular Surgery and Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital and Academy, Gothenburg, Sweden.
authors.forename: Klas
authors.initials: K
authors.lastname: Osterberg
authors.affiliation: Department of Vascular Surgery and Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital and Academy, Gothenburg, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Jivegård
mesh_terms: D056044:Actigraphy; D000368:Aged; D040421:Cell Phone; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D007383:Intermittent Claudication / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology; D008297:Male; D008875:Middle Aged; D063731:Mobile Applications; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011788:Quality of Life; D011795:Surveys and Questionnaires; D013997:Time Factors; D016138:Walking