Risk Factors for In-hospital Mortality and Reamputation Following Lower Limb Amputation

Abstract

Objective: Studies on the outcomes of lower limb amputation have been limited by the use of selected study populations and small sample sizes. Although reamputation is an important outcome following lower limb amputation, the risk factors for reamputation remain to be elucidated. The present study was performed to identify risk factors for in-hospital death and reamputation following lower limb amputation. Methods: Using a national inpatient database in Japan, we identified 13,774 patients who underwent lower limb amputation. We examined the patients’ backgrounds and employed a multivariable logistic regression analysis to identify factors associated with in-hospital death or reamputation. Results: The average age of the 13,774 patients was 72.4 years, and 63.1% (n=8694) were male. The overall in-hospital mortality rate was 10.8% (1481/13,774). The reamputation rate was 10.1% (782/7779) for patients who initially underwent foot or transtibial amputation (18.2% [391/2148] for foot amputations and 6.9% [391/5631] for transtibial amputations). Multivariable logistic regression analysis revealed higher age, male sex, peripheral vascular disease, use of insulin, hemodialysis, and higher numbers of comorbidities as significant risk factors for reamputation or in-hospital death. Use of hemodialysis was the strongest risk factor (odds ratio, 2.10; 95% confidence interval, 1.87–2.35). Conclusions: The in-hospital mortality and reamputation rates following lower limb amputation were considerably high, reflecting the severely ill conditions of patients with advanced chronic diseases. Risk factors for in-hospital death and reamputation following lower limb amputation were identified. These should aid surgeons in determining a patient’s risk of a poor outcome and deciding on the level of amputation.