Patients with dementia or frailty undergoing major limb amputation have poor outcomes.

Objective: Major lower limb amputation is a disfiguring operation associated with impaired mobility and high near-term mortality. Informed decision-making regarding amputation requires outcomes data. Despite the co-occurrence of both chronic limb-threatening ischemia (CLTI) and Alzheimer's disease and related dementias (ADRD), there is sparse data on the outcomes of major limb amputation in this population and the impact of frailty. We sought to determine mortality, complications, readmissions, revisions, intensive interventions (eg, cardiopulmonary resuscitation), and other outcomes after amputation for CLTI in patients living with ADRD looking at the modifying effects of frailty.

Methods: We examined Medicare fee-for-service claims data from January 1, 2016, to December 31, 2020. Patients with CLTI undergoing amputation at or proximal to the ankle were included. Along with demographic information, dementia status, and comorbid conditions, we measured frailty using a claims-based frailty index. We dichotomized dementia and frailty (pre-frail/robust = "non-frail" vs moderate/severe frailty = "frail") to create four groups: non-frail/non-ADRD, frail/non-ADRD, non-frail/ADRD, and frail/ADRD. We used linear and logistic regression via generalized estimating equations in addition to performing selected outcomes analyses with death as a competing risk to understand the association between dementia status, frailty status, and 1-year mortality as our primary outcome in addition to the postoperative outcomes outlined above.

Results: Among 46,930 patients undergoing major limb amputation, 11,465 (24.4%) had ADRD and 24,790 (52.8%) had frailty. Overall, 55.9% of amputations were below-knee. Selected outcomes among frail/ADRD patients undergoing amputation (n = 10,153) were: 55.3% 1-year mortality 29.6% readmissions at 30 days, and 32.3% amputation revision/reoperation within 1 year. Of all four groups, those in the frail/ADRD had the worst outcomes only for 1-year mortality.

Conclusions: First, patients with ADRD or moderate/severe frailty suffer an array of very poor outcomes after major limb amputation for CLTI, including high mortality, readmissions, revision, and risks of discharge to higher levels of care. Second, there is a complex relationship between outcome severity and ADRD/frailty status. Specifically, frailty is more often than ADRD associated with the poorest results for any given outcome. These data provide important outcomes data to help align decision-making with health care values and goals.