An elevated neutrophil-lymphocyte ratio independently predicts mortality in chronic critical limb ischemia

Atherogenesis represents an active inflammatory process with leucocytes playing a major role. An elevated white blood cell count has been shown to be predictive of death in coronary artery disease patients. The aim of this study was to examine the predictive ability of neutrophil count and neutrophil/lymphocyte ratio for predicting survival in patients with critical lower limb ischemia (CLI).

All patients admitted to a single vascular unit with CCLI were identified prospectively over a 2-year period starting from January 2005. Patient demographics, clinical history, comorbidity, and risk factors for peripheral vascular disease were documented. The white blood count and differential cell count at admission was recorded. Overall, patient mortality was studied as the primary outcome.

One hundred forty-nine patients were identified, with a median age of 72 years (Interquartile range [IQR], 65.7-81). A neutrophil-lymphocyte ratio (NLR) of >or=5.25 was taken as the cutoff, based upon the receiver-operating-characteristic.The median follow up was 8.7 months (IQR, 3.1-16). During the follow-up period, there have been 62 deaths (43.4%). An elevated neutrophil/lymphocyte ratio and a high troponin level (>0.1) were found to be the only two factors independently associated with shorter survival on multivariate analysis using the Cox proportional hazards model.

This study suggests that an elevated NLR can identify a poor-risk subset of patients among those being treated for critical limb ischemia. This simple, inexpensive test may, therefore, add to risk stratification of these high-risk patients.