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

Abstract

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.