title: Decline in functional performance predicts later increased mobility loss and mortality in peripheral arterial disease.
abstract: OBJECTIVE
  We hypothesized that a greater 2-year decline in office-based functional performance measures would be associated with greater mobility loss and mortality in people with peripheral arterial disease (PAD).
  
  
  BACKGROUND
  Associations of decline in functional performance with clinically important outcomes in patients with PAD are unknown.
  
  
  METHODS
  A total of 440 men and women with PAD completed the 6-min walk test and measures of walking velocity at baseline and annually for 2 years. Participants were categorized into tertiles according to their functional decline between baseline and 2-year follow-up and were followed annually after the functional change assessment. Cox proportional hazard models were used to assess relations between the 2-year change in functional performance with later mortality and mobility loss, with adjustments for age, sex, race, ankle brachial index, comorbidities, and other confounders.
  
  
  RESULTS
  A total of 102 participants (23.2%) died during a median follow-up of 44.5 months after functional change was assessed. Of 319 participants without baseline mobility disability, 60 (18.8%) developed mobility loss after functional change was assessed. Participants in the tertile with the greatest 6-min walk decline had the highest subsequent mobility loss (hazard ratio [HR]: 3.50; 95% confidence interval [CI]: 1.56 to 7.85; p = 0.002), all-cause mortality (HR: 2.16; 95% CI: 1.28 to 3.64; p = 0.004), and cardiovascular disease mortality (HR: 2.45; 95% CI: 1.08 to 5.54; p = 0.031), compared with those with the smallest 6-min walk decline. Greater declines in fastest-paced 4-m walking velocity were associated with higher mobility loss (p trend = 0.018), all-cause mortality (p trend = 0.01), and cardiovascular mortality (p trend = 0.004).
  
  
  CONCLUSIONS
  Participants with PAD with declining functional performance are at increased risk for later mobility loss and mortality.
authors.affiliation: Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA. mdm608@northwestern.edu
authors.forename: Mary M
authors.initials: MM
authors.lastname: McDermott
authors.forename: Kiang
authors.initials: K
authors.lastname: Liu
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: Lu
authors.initials: L
authors.lastname: Tian
authors.forename: Jack M
authors.initials: JM
authors.lastname: Guralnik
authors.forename: Yihua
authors.initials: Y
authors.lastname: Liao
authors.forename: Michael H
authors.initials: MH
authors.lastname: Criqui
mesh_terms: D000367:Age Factors; D000368:Aged; D055109:Ankle Brachial Index; D002423:Cause of Death; D015331:Cohort Studies; D004185:Disability Evaluation; D018450:Disease Progression; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000401:mortality* / Q000503:physiopathology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012720:Severity of Illness Index; D012737:Sex Factors; D015996:Survival Rate; D013997:Time Factors; D016138:Walking / Q000502:physiology