The Relationship Between Obesity and Amputation-free Survival in Patients Undergoing Lower-limb Revascularisation for Chronic Limb-threatening Ischaemia: A Retrospective Cohort Study

Background

The obesity paradox is a well-documented phenomenon in cardiovascular disease, however it remains poorly understood. We aimed to investigate the relationship between body mass (as measured by body mass index [BMI]) and 1-year amputation-free survival (AFS) for patients undergoing lower limb revascularisation for chronic limb-threatening ischaemia (CLTI).

Methods

A retrospective analysis was undertaken of all consecutive patients undergoing lower limb revascularisation for CLTI at the Leicester Vascular Institute between February 2018–19. Baseline demographics and outcomes were collected using electronic records. BMI was stratified using the World Health Organization criteria. One-year AFS (composite of major amputation/death) was the primary outcome. Kaplan-Meier survival analysis and adjusted Cox's proportional hazard models were used to compare groups to patients of normal mass.

Results

One-hundred and ninety patients were included. Overall, no difference was identified in 1-year AFS across all groups (pooled P = 0.335). Compared to patients with normal BMI (n = 66), obese patients (n = 43) had a significantly lower adjusted combined risk of amputation/death (aHR 0.39, 95% CI 0.16–0.92, P = 0.032), however no significant differences were observed for overweight (aHR 0.89, 95% CI 0.47–1.70, P = 0.741), morbidly obese (aHR 1.15, 95% CI 0.41–3.20, P = 0.797) and underweight individuals (aHR 1.86, 95% CI 0.56–6.20, P = 0.314).

Conclusions

In the context of CLTI, obesity is potentially associated with favourable amputation-free survival at 1 year, compared to normal body mass. The results of this study support the notion of an obesity paradox existing within CLTI and question whether current guidance on weight management requires a more patient-specific approach.