Mortality, re-amputation and post operative complication rates following 28,000 below knee amputation in diabetic patients in England: a national population study 2002-2022.

Mr Conor Hennessy1, S Abram, C Loizou, R Brown, B Sharp, A Kendal

Introduction: Global data on BKA mortality is dominated by US Veterans population studies, while smaller single centre UK cohorts observe a wide range of 1 year mortality (13.8%-61.1%). There is no consensus on mortality rates, perioperative complications and at-risk groups post diabetic BKA in England.

Methods: England Hospital Episodes Statistics (HES) data was combined with ONS mortality data (2000-2022) and cleaned using STATA 18. The primary outcome was the rate of all cause mortality. Secondary outcomes were causes of death, re-amputation rates, temporal variation in mortality, and 90 day peri-operative complications. Mortality and amputation free survival was calculated with Kaplan-Meier curve analysis using R, STATA 18. Multivariate logistic regression stratified patient variables associated with mortality and/or re-amputation rate.

Results: 28,045 BKA were performed for diabetes in the 20-year period; decreasing from 8.1/100,000 (2002) to 6.5/100,000 (2022). The rates were significantly higher in white males aged 60-79 years old (14/100,000 in 2023). The mortality rates following BKA for diabetic foot disease were 7.1% at 30 days, 12.7% at 90 days, 24.6% at 1 year, and 61.2% at 5 years. Only 17% of patients survived to 10 years post BKA. The 90-day reoperation rate for any cause was 20.7%. The ipsilateral re-amputation rate at any time was 10.4% (n=2909), and the contralateral amputation rate was 8.2% (n=2304). Additional 90-day complications included PE (0.75%, n=211), MI (3.6%, n=1019) and Stroke (1.1%, n=316). Multi-regression analysis demonstrated significantly higher BKA associated mortality rates at all time points in male, British-Asians with higher deprivation status.

Conclusions: This landmark 20-year England diabetic population study has revealed high rates of death, further amputation and peri-operative morbidity post BKA. Asian Males in their 60s have the highest mortality rates and represent an at-risk group. Overall, there has been little improvement in post BKA mortality over the last 20 years.