title: Functional decline in lower-extremity peripheral arterial disease: associations with comorbidity, gender, and race.
abstract: OBJECTIVE
  To identify comorbidities associated with increased rates of functional decline in persons with lower-extremity peripheral arterial disease (PAD). We also determined whether female sex and black race were associated with greater functional decline than male sex and white race, respectively, in PAD.
  
  
  METHODS
  Three-hundred ninety-seven men and women with PAD were followed prospectively for a median of 36 months. The presence of comorbid illnesses was determined with medical record review, patient report, medications, laboratory values, and a primary care physician questionnaire. Functional outcomes, measured annually, included the 6-minute walk, usual-paced and fast-paced 4-meter walking speed, and summary performance score. The summary performance score is a composite measure of lower-extremity functioning (score range, 0 to 12; 12 = best).
  
  
  RESULTS
  Adjusting for known and potential confounders, PAD patients with pulmonary disease had a significantly greater average annual decline in 6-minute walk performance of -34.02 ft/y (95% confidence interval [CI], -60.42 to -7.63; P = .012), rapid-paced 4-meter walk speed of -0.028 m/s/y (95% CI, -0.054 to -0.001; P = .042), and summary performance score of -0.460/y (95% CI, -0.762 to -0.157; P = .003) compared with those without pulmonary disease. PAD patients with spinal stenosis had a greater average annual decline in 6-minute walk performance of -77.4 ft/y (95% CI, -18.9 to -35.8; P < .001) and usual-paced 4-meter walking velocity of -0.045 m/s/y (95% CI, -0.081 to -0.009; P = .014) compared with participants without spinal stenosis.
  
  
  CONCLUSIONS
  At 3-year follow-up, pulmonary disease and spinal stenosis were each associated with a significant decline in functioning among persons with PAD. In contrast, female sex and black race were not associated with functional decline among persons with PAD.
authors.affiliation: Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. mdm608@northwestern.edu
authors.forename: Mary M
authors.initials: MM
authors.lastname: McDermott
authors.forename: Jack M
authors.initials: JM
authors.lastname: Guralnik
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: Michael H
authors.initials: MH
authors.lastname: Criqui
authors.forename: Philip
authors.initials: P
authors.lastname: Greenland
authors.forename: Lu
authors.initials: L
authors.lastname: Tian
authors.forename: Kiang
authors.initials: K
authors.lastname: Liu
authors.forename: Jin
authors.initials: J
authors.lastname: Tan
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000150:complications / Q000503:physiopathology*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000503:physiopathology*; D008171:Lung Diseases / Q000150:complications*; D008297:Male; D011446:Prospective Studies; D012720:Severity of Illness Index; D013130:Spinal Stenosis / Q000150:complications*; D011795:Surveys and Questionnaires; D013997:Time Factors; D016138:Walking / Q000502:physiology*