One-Year Change in Walking Performance and Subsequent Mobility Loss and Mortality Rates in Peripheral Artery Disease: Longitudinal Data From the WALCS

BACKGROUND: Associations of 1-year change in functional performance measures with subsequent mobility loss and mortality in people with lower extremity peripheral artery disease are unknown. METHODS AND RESULTS: Six-minute walk and 4-meter walking velocity (usual and fastest pace) were measured at baseline and 1year later in 612 people with peripheral artery disease (mean age 71±9 years, 37% women). Participants were categorized into tertiles, based on 1-year changes in walking measures. Cox proportional hazards models were used to examine associations between 1-year change in each walking measure and subsequent mobility loss and mortality, respectively, adjusting for potential confounders. Compared with the best tertile, the worst tertile (ie, greatest decline) in 1-year change in each performance measure was associated with higher rates of mobility loss: 6-minute walk (Tertile 1 [T1] cumulative incidence rate [IR], 72/160; Tertile 3 [T3] IR, 47/160; hazard ratio [HR], 2.35; 95% CI, 1.47–3.74), usual-paced 4-meter walking velocity (T1 IR, 54/162; T3 IR, 57/162; HR, 2.21; 95% CI, 1.41–3.47), and fast-paced 4-meter walking velocity (T1 IR, 61/162; T3 IR, 58/162; HR, 1.81; 95% CI, 1.16–2.84). Compared with the best tertile, the worst tertiles in 1-year change in 6-minute walk (T1 IR, 66/163; T3 IR, 54/163; HR, 1.61; 95% CI, 1.07–2.43) and fast-paced 4-meter walking velocity (T1 IR, 63/166; T3 IR, 44/166; HR, 1.75; 95% CI, 1.16, 2.64) were associated with higher mortality. CONCLUSIONS: In people with peripheral artery disease, greater 1-year decline in 6-minute walk or 4-meter walking velocity may help identify people with peripheral artery disease at highest risk for mobility loss and mortality.