Neutrophil-lymphocyte ratio: A prognostic tool in patients with in-hospital cardiac arrest

In-hospital cardiac arrest (IHCA) portends a poor prognosis and survival to discharge rate. Prognostic markers such as interleukin-6, S-100 protein and high sensitivity C reactive protein have been studied as predictors of adverse outcomes after return of spontaneous circulation (ROSC); however; these variables are not routine laboratory tests and incur additional cost making them difficult to incorporate and less attractive in assessing patient's prognosis. The neutrophil-lymphocyte ratio (NLR) is a marker of adverse prognosis for many cardiovascular conditions and certain types of cancers and sepsis. We hypothesize that an elevated NLR is associated with poor outcomes including mortality at discharge in patients with IHCA.

To determine the prognostic significance of NLR in patients suffering IHCA who achieve ROSC.

A retrospective study was performed on all patients who had IHCA with the advanced cardiac life support protocol administered in a large urban community United States hospital over a one-year period. Patients were divided into two groups based on their NLR value (NLR < 4.5 or NLR ≥ 4.5). This cutpoint was derived from receiving operator characteristic curve analysis (area under the curve = 0.66) and provided 73% positive predictive value, 82% sensitivity and 42% specificity for predicting in-hospital death after IHCA. The primary outcome was death or discharge at 30 d, whichever came first.

We reviewed 153 patients with a mean age of 66.1 ± 16.3 years; 48% were female. In-hospital mortality occurred in 65%. The median NLR in survivors was 4.9 (range 0.6-46.5) compared with 8.9 (0.28-96) in non-survivors (P = 0.001). A multivariable logistic regression model demonstrated that an NLR above 4.55 [odds ratio (OR) = 5.20, confidence interval (CI): 1.5-18.3, P = 0.01], older age (OR = 1.03, CI: 1.00-1.07, P = 0.05), and elevated serum lactate level (OR = 1.20, CI: 1.03-1.40, P = 0.02) were independent predictors of death.

An NLR ≥ 4.5 may be a useful marker of increased risk of death in patients with IHCA.