The impact of diabetes on mortality rates after lower extremity amputation

Objective: To assess the impact of diabetes, amputation level, sex and age on mortality rates after lower extremity amputation (LEA) in Belgium, and to assess temporal trends in one-year survival rates from 2009 to 2018. Methods: Nationwide data on individuals who underwent minor and major LEA from 2009 to 2018 were collected. Kaplan-Meier survival curves were constructed. A Cox regression model with time-varying coefficients was used to estimate the likelihood of mortality after LEA in individuals with or without diabetes. Matched amputation-free individuals with or without diabetes were used for comparison. Time trends were analysed. Results: Amputations 41,304 were performed: 13,247 major and 28,057 minor. Five-year mortality rates in individuals with diabetes were 52% and 69% after minor and major LEA, respectively (individuals without diabetes: 45% and 63%, respectively). In the first six postoperative months, no differences in mortality rates were found between individuals with or without diabetes. Later, hazard ratios (HRs) for mortality in individuals with diabetes (compared with no diabetes) after minor LEA ranged from 1.38 to 1.52, and after major LEA from 1.35 to 1.46 (all p = 0.005). Among individuals without LEA, HRs for mortality in diabetes (versus no diabetes) were systematically higher compared to the HRs for mortality in diabetes (versus no diabetes) after minor and major LEA. One-year survival rates did not change for individuals with diabetes. Conclusions: In the first six postoperative months, mortality rates after LEA were not different between individuals with or without diabetes; later, diabetes was significantly associated with increased mortality. However, as HRs for mortality were higher in amputation-free individuals, diabetes impacts mortality less in the minor and major amputation groups relative to the comparison group of individuals without LEA.