Illness Trajectories After Revascularization in Patients With Peripheral Artery Disease: A Unified Approach to Understanding the Risk of Major Amputation and Death

BACKGROUND: The aim of this study was to investigate the illness trajectories of patients with peripheral artery disease (PAD) after revascularization and estimate the independent risks of major amputation and death (from any cause) and their interaction. METHODS: Data from Hospital Episode Statistics Admitted Patient Care were used to identify patients (>= 50 years of age) who underwent lower limb revascularization for PAD in England from April 2013 to March 2020. A Markov illness-death model was developed to describe patterns of survival after the initial lower limb revascularization, if and when patients experienced major amputation, and survival after amputation. The model was also used to investigate the association between patient characteristics and these illness trajectories. We also analyzed the relative contribution of deaths after amputation to overall mortality and how the risk of mortality after amputation was related to the time from the index revascularization to amputation. RESULTS: The study analyzed 94 690 patients undergoing lower limb revascularization for PAD from 2013 to 2020. The majority were men (65.6%), and the median age was 72 years (interquartile range, 64-79). One-third (34.8%) of patients had nonelective revascularization, whereas others had elective procedures. For nonelective patients, the amputation rate was 15.2% (95% CI, 14.4-16.0) and 19.9% (19.0-20.8) at 1 and 5 years after revascularization, respectively. For elective patients, the corresponding amputation rate was 2.7% (95% CI, 2.4-3.1) and 5.3% (4.9-5.8). Overall, the risk of major amputation was higher among patients who were younger, had tissue loss, diabetes, greater frailty, nonelective revascularization, and more distal procedures. The mortality rate at 5 years after revascularization was 64.3% (95% CI, 63.2-65.5) for nonelective patients and 33.0% (32.0-34.1) for elective patients. After major amputation, patients were at an increased risk of mortality if they underwent major amputation within 6 months after the index revascularization. CONCLUSIONS: The illness-death model provides an integrated framework to understand patient outcomes after lower limb revascularization for PAD. Although mortality increased with age, the study highlights patients <60 years of age were at increased risk of major amputation, particularly after nonelective revascularization.