Graeme K Ambler1, Emma Thomas-Jones2, Adrian G K Edwards3, Christopher P Twine4. 1. Bristol Centre for Surgical Research, University of Bristol and North Bristol NHS Trust, Southmead Hospital, Bristol, UK. Electronic address: graeme.ambler@gmail.com. 2. Centre for Trials Research, Cardiff University, 7th Floor, Neuadd Meirionnydd, Heath Park, Cardiff, CF14 4XW, UK. 3. Division of Population Medicine, Cardiff University, 8th Floor, Neuadd Meirionnydd, Heath Park, Cardiff, CF14 4XW, UK. 4. Bristol Centre for Surgical Research, University of Bristol and North Bristol NHS Trust, Southmead Hospital, Bristol, UK.
Abstract
OBJECTIVE: Major lower limb amputation is the highest risk lower limb procedure in vascular surgery. Despite this, few high quality studies have examined factors contributing to mortality. The aim was to identify independent risk factors for peri-operative morbidity and mortality and develop reliable models for estimating risk. METHODS: All patients undergoing lower limb amputation above the ankle entered into the UK National Vascular Registry (January 2014-December 2016) were included. Missing data were handled using multiple imputation. Models were developed to evaluate independent risk factors for mortality (the primary outcome) and morbidity using logistic regression, minimising the Bayesian information criterion to balance complexity and model fit. Ethical approval for the study was granted (Wales REC 3 ref:16/WA/0353). RESULTS: All 9549 above ankle joint amputations in the registry were included. Overall, 865 patients (9.1%) died before leaving hospital. Independent factors associated with mortality were emergency admission, bilateral operation, age, American Society of Anesthesiologists' grade, abnormal electrocardiogram, and increased white cell count or creatinine (p < .01 for all). Independent factors reducing mortality were transtibial operation, increased albumin or patient weight, and previous ipsilateral revascularisation procedures (p < .01 for all). A risk model incorporating these factors had good discrimination (C-statistic 0.79, 95% confidence interval 0.77-0.80) and excellent calibration. Morbidity rates were high, with 6.6%, 9.7%, and 4.3% of patients suffering cardiac, respiratory, and renal complications, respectively. The risk model was also predictive of morbidity outcomes (C-statistics 0.74, 0.69, and 0.74, respectively). CONCLUSION: Morbidity and mortality after lower limb amputation are high in the UK. Some potentially modifiable factors for quality improvement initiatives have been identified and accurate predictive models that could assist patient counselling and decision making have been developed.
OBJECTIVE: Major lower limb amputation is the highest risk lower limb procedure in vascular surgery. Despite this, few high quality studies have examined factors contributing to mortality. The aim was to identify independent risk factors for peri-operative morbidity and mortality and develop reliable models for estimating risk. METHODS: All patients undergoing lower limb amputation above the ankle entered into the UK National Vascular Registry (January 2014-December 2016) were included. Missing data were handled using multiple imputation. Models were developed to evaluate independent risk factors for mortality (the primary outcome) and morbidity using logistic regression, minimising the Bayesian information criterion to balance complexity and model fit. Ethical approval for the study was granted (Wales REC 3 ref:16/WA/0353). RESULTS: All 9549 above ankle joint amputations in the registry were included. Overall, 865 patients (9.1%) died before leaving hospital. Independent factors associated with mortality were emergency admission, bilateral operation, age, American Society of Anesthesiologists' grade, abnormal electrocardiogram, and increased white cell count or creatinine (p < .01 for all). Independent factors reducing mortality were transtibial operation, increased albumin or patient weight, and previous ipsilateral revascularisation procedures (p < .01 for all). A risk model incorporating these factors had good discrimination (C-statistic 0.79, 95% confidence interval 0.77-0.80) and excellent calibration. Morbidity rates were high, with 6.6%, 9.7%, and 4.3% of patients suffering cardiac, respiratory, and renal complications, respectively. The risk model was also predictive of morbidity outcomes (C-statistics 0.74, 0.69, and 0.74, respectively). CONCLUSION: Morbidity and mortality after lower limb amputation are high in the UK. Some potentially modifiable factors for quality improvement initiatives have been identified and accurate predictive models that could assist patient counselling and decision making have been developed.
Authors: Sarah Milosevic; Lucy Brookes-Howell; Brenig Llwyd Gwilym; Cherry-Ann Waldron; Emma Thomas-Jones; Ryan Preece; Philip Pallmann; Debbie Harris; Ian Massey; Philippa Stewart; Katie Samuel; Sian Jones; David Cox; Christopher P Twine; Adrian Edwards; David C Bosanquet Journal: BMJ Open Date: 2022-01-17 Impact factor: 3.006
Authors: Brenig L Gwilym; Cherry-Ann Waldron; Emma Thomas-Jones; Ryan Preece; Sarah Milosevic; Lucy Brookes-Howell; Philip Pallmann; Debbie Harris; Ian Massey; Jo Burton; Philippa Stewart; Katie Samuel; Sian Jones; David Cox; Adrian Edwards; Chris Twine; David C Bosanquet Journal: BJS Open Date: 2021-11-09