The impact of comorbidities on mortality in patients with non-traumatic major lower extremity amputation

Abstract

Objective: Major lower limb amputation is generally associated with a high risk of early and late-term mortality. In this study, 30-day, one-year and three-year mortality of non-traumatic major lower extremity amputations and comorbidities affecting the mortality rate were investigated. Method: Patients who underwent a major lower limb amputation secondary to diabetes or peripheral artery disease between the years 2010–2015 were retrospectively evaluated. Additional to patient demographic data and comorbidities, amputation level, survival and mortality time were extracted. Mortality rates after 30 days, one year and three years were analysed. The associations of the survival to different parameters were evaluated with Kaplan–Meier analysis and log rank test, while the impact of the risk factors on mortality was evaluated with the Cox regression test. Results: A total of 193 patients were enrolled in the study. Approximately 60% of patients were aged ≥65 years, and 65.8% were male. Below-knee amputation was performed in 64.8% of patients and above-knee amputation in 35.2% of patients. The mean follow-up of patients was 29.48 months (range: 0–101 months). After non-traumatic major lower extremity amputation, 30-day, one-year and three-year mortality were 16.6%, 38.3% and 60.1%, respectively. On Cox regression analysis, age ≥65 years was the only variable that had significant impact on the 30-day mortality (hazard ratio (HR): 3.4; p=0.012), while age ≥65 years (HR: 2.5, p=0.000), diabetes (HR: 2, p=0.006) and renal failure (HR: 2, p=0.001) were found to have significant impacts on three-year mortality. Conclusion: The findings of this study showed that >50% of patients with non-traumatic major lower limb amputations died within three years. Advanced age, diabetes and renal failure were the risk factors that increased the mortality. The high mortality rates revealed the importance of employing all hard-to-heal wound treatment options before making an amputation decision. Further, prospective studies are needed to determine the effects of primary disease status and timing of amputation on mortality.