title: Neutrophil Lymphocyte Ratio as a predictor of systemic inflammation - A cross-sectional study in a pre-admission setting.
abstract: BACKGROUND
  Neutrophil:lymphocyte ratio (NLR)  is an emerging biomarker that is used to predict postoperative mortality and morbidity in cardiac and cancer surgeries. The association of this biomarker with systemic illness and its usefulness in risk assessment of preoperative patients has not been fully elucidated.
  
  
  OBJECTIVE
  To determine the prevalence of elevated NLR in preoperative patients and to examine the relationship between elevated NLR and the presence of systemic illnesses as well as anaesthesia risk indices such as American Society of Anesthesia (ASA) and the revised cardiac risk index (RCRI) scores.
  
  
  METHODS
  Cross-sectional study Setting: Anaesthesia pre-admission clinic, Toronto Western Hospital, Toronto, Canada Patients: We evaluated 1117 pre-operative patients seen at an anesthesia preadmission clinic.
  
  
  RESULTS
  NLR was elevated (>3.3) in 26.6% of target population. In multivariate analysis, congestive cardiac failure, diabetes mellitus and malignancy were independent risk factors predicting raised NLR. After regression analysis, a relationship between NLR and ASA score (Odds Ratio 1.78; 95% CI: 1.42-2.24) and revised cardiac risk index (RCRI, odds ratio 1.33; 95% CI: 1.09-1.64, p-value: 0.0063) was observed.
  
  
  CONCLUSIONS
  NLR was elevated (> 3.3) in 26.6% of patients. Congestive cardiac failure and malignancy were two constant predictors of elevated NLR at >3.3 and > 4.5. There was a strong association between NLR and anesthesia risk scoring tools of ASA and RCRI.
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, Ontario, M5T 2S8, Canada.
authors.forename: Lashmi
authors.initials: L
authors.lastname: Venkatraghavan
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, Ontario, M5T 2S8, Canada.
authors.forename: Tze Ping
authors.initials: TP
authors.lastname: Tan
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, Ontario, M5T 2S8, Canada.
authors.forename: Jigesh
authors.initials: J
authors.lastname: Mehta
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, Ontario, M5T 2S8, Canada.
authors.forename: Anil
authors.initials: A
authors.lastname: Arekapudi
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, Ontario, M5T 2S8, Canada.
authors.forename: Arun
authors.initials: A
authors.lastname: Govindarajulu
authors.affiliation: Department of Anesthesia, Toronto Western Hospital, University Health Network, Toronto, Ontario, M5T 2S8, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Siu
keywords: Neutrophil Lymphocyte Ratio; Revised Cardiac Risk Index