title: Claudication distances and the Walking Impairment Questionnaire best describe the ambulatory limitations in patients with symptomatic peripheral arterial disease.
abstract: BACKGROUND
  Claudication secondary to peripheral arterial disease leads to reduced mobility, limited physical functioning, and poor health outcomes. Disease severity can be assessed with quantitative clinical methods and qualitative self-perceived measures of quality of life. Limited data exist to document the degree to which quantitative and qualitative measures correlate. The current study provides data on the relationship between quantitative and qualitative measures of symptomatic peripheral arterial disease.
  
  
  METHODS
  This descriptive case series was set in an academic vascular surgery unit and biomechanics laboratory. The subjects were symptomatic patients with peripheral arterial disease patients presenting with claudication. The quantitative evaluation outcome measures included measurement of ankle-brachial index, initial claudication distance, absolute claudication distance, and self-selected treadmill pace. Qualitative measurements included the Walking Impairment Questionnaire (WIQ) and the Medical Outcomes Study Short Form-36 (SF-36) Health Survey. Spearman rank correlations were performed to determine the relationship between each quantitative and qualitative measure and also between the WIQ and SF-36.
  
  
  RESULTS
  Included were 48 patients (age, 62 +/- 9.6 years; weight, 83.0 +/- 15.4 kg) with claudication (ABI, 0.50 +/- 0.20). Of the four WIQ subscales, the ankle-brachial index correlated with distance (r = 0.29) and speed (r = 0.32); and initial claudication distance and absolute claudication distance correlated with pain (r = 0.40 and 0.43, respectively), distance (r = 0.35 and 0.41, respectively), and speed (r = 0.39 and 0.39 respectively). Of the eight SF-36 subscales, no correlation was found for the ankle-brachial index, initial claudication distance correlated with Bodily Pain (r = 0.46) and Social Functioning (r = 0.30), and absolute claudication time correlated with Physical Function (r = 0.31) and Energy (r = 0.30). The results of both questionnaires showed reduced functional status in claudicating patients.
  
  
  CONCLUSIONS
  Initial and absolute claudication distances and WIQ pain, speed, and distance subscales are the measures that correlated the best with the ambulatory limitation of patients with symptomatic peripheral arterial disease. These results suggest the WIQ is the most specific questionnaire for documenting the qualitative deficits of the patient with claudication while providing strong relationships with the quantitative measures of arterial disease. Future studies of claudication patients should include both quantitative and qualitative assessments to adequately assess disease severity and functional status in peripheral arterial disease patients.
authors.affiliation: Heath, Physical Education, and Recreation (HPER) Biomechanics Laboratory, University of Nebraska Medical Center, Omaha 68198-3280, USA.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Myers
authors.forename: Jason M
authors.initials: JM
authors.lastname: Johanning
authors.forename: Nick
authors.initials: N
authors.lastname: Stergiou
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Lynch
authors.forename: G Matthew
authors.initials: GM
authors.lastname: Longo
authors.forename: Iraklis I
authors.initials: II
authors.lastname: Pipinos
mesh_terms: D000368:Aged; D000842:Ankle / Q000098:blood supply; D001794:Blood Pressure; D001916:Brachial Artery / Q000503:physiopathology; D016022:Case-Control Studies; D004185:Disability Evaluation; D006801:Humans; D007383:Intermittent Claudication / Q000209:etiology* / Q000503:physiopathology; D007484:Iowa; D008875:Middle Aged; D051346:Mobility Limitation; D009329:Nebraska; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D016491:Peripheral Vascular Diseases / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016138:Walking