The Neutrophil–Lymphocyte Ratio is a Predictor of 1-Year Survival Following Major Limb Amputation

Introduction - Major amputation is often the only intervention available for patients presenting with irretractable pain, tissue loss or severe infection and no revascularisation options. Mortality following amputation for critical limb ischaemia (CLI) is especially high. The neutrophil-lymphocyte ratio (NLR) has been shown to predict survival in patients presenting with CLI as well as those undergoing open repair of both ruptured and non-ruptured abdominal aortic aneurysms. The aim of this study was to assess the NLR’s value as a predictor of 1-year survival in patients following major amputation. Methods - Consecutive patients undergoing above- or below-knee amputation for CLI in a single vascular centre between November 2014 and January 2016 were considered for this study. Total white blood cell count and its differential prior to amputation were recorded. Patients were followed up for 1 year and all-cause mortality documented. Results - 90 patients were included in the study: 68 men, 22 women; median age 72 (IQR 65-78.). There were 31 mortalities (34%) in the follow-up period with a median time to death of 45 days. Mean NLR in patients who died was higher than those who survived (16.7 vs. 8.1, p<0.01). There was however no significant difference in total white cell count between groups (13.9 vs. 12.5, p=0.3089). An NLR of >7.2 was considered raised based on the receiver operating characteristic. 45 (50%) patients had a raised NLR prior to amputation. Survival at 1 year was 78% in the low NLR group compared to 53% in the high NLR group (p<0.05). Conclusion - The NLR is a simple, cheap and accessible test that can be used to predict survival in patients undergoing major limb amputation for critical limb ischaemia. Its prognostic value is maintained out to 1 year. Use of the NLR can help risk-stratify patients, thereby assisting in shared decision-making and identifying those likely to benefit from enhanced pre-, peri- and post-operative care.