Factors that affect the one-year mortality rate after lower limb amputation in the Hong Kong Chinese population

Introduction: Lower limb amputation has significant morbidity and mortality. This study reviews the potential factors affecting the one-year mortality rate after lower limb amputation in the Hong Kong Chinese population. Methods: Cases with lower limb amputations (toe, ray, below-knee, and above-knee amputations) from a regional hospital from January 2016 to December 2017 were recruited. Amputations due to trauma were excluded. The one-year mortality rate and the potential risk factors (age, sex, length-of-stay, multiple operations, extent of surgery (minor vs. major), medical comorbidities including (1) end-stage renal failure (ESRF), (2) cardiac diseases, (3) ischemic heart disease, (4) peripheral vascular disease and (5) diabetes mellitus) were analyzed by multiple logistic regression using Matlab 2018a. Results: A total of 132 patients were recruited (173 operations). The one-year mortality rate was 36.3%. The mean age at death was 72.2 years. The results of the regression analysis showed patients having ESRF (β = 2.195, t 120 = 3.008, p = 0.003) or a major amputation (including above- or below-knee amputation) (β = 1.079, t 120 = 2.120, p = 0.034), had a significantly higher one-year mortality. The remaining factors showed no significant effect. The one-year mortality rate in ESRF patients was 77.8%; while the one-year mortality rate without ESRF was 29.8%. The mean age at death in the ESRF group was 62.9 years; while that without ESRF was 76.1 years. The one-year mortality for patients with major amputation was 45.8% while that for minor amputation was 20.4%. Conclusion: ESRF and major amputation are factors that increase the one-year mortality rate after lower limb amputation.