Decline in functional performance predicts later increased mobility loss and mortality in peripheral arterial disease

Abstract

Objectives: 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.

Figure 1. Depiction of eligible participants from the WALCS and WALCS II cohorts

*Excluded because they did not return annually for 2 years for functional assessment after baseline (N=198), they underwent lower extremity revascularization during the first 2 years of follow-up (N=48), they were lost to follow-up after their two-year functional change assessment (N=8) or they had missing variables in the fully adjusted models (N=6). †Excluded because they met criteria for mobility disability between baseline and 2-year follow-up (N=76) or they were missing data on their mobility status during follow-up (N=45) WALCS – Walking and Leg Circulation Study