Neutrophil-to-lymphocyte ratio: an accurate method for diagnosing infection in cirrhosis

Early diagnosing bacterial infection in cirrhotic patients is critical but challenging. Neutrophil-to-lymphocyte ratio (NLR) reflects systemic inflammation and is an emerging biomarker that replicates cirrhosis' imbalanced immune response.

Assess whether NLR levels associate with higher risk of infection in patients admitted with first cirrhosis decompensation.

Retrospective, unicenter study, including patients with cirrhosis, admitted to the hospital at first decompensation. NLR was calculated at admission. Applying logistic regression models and testing for discriminative power, we correlated NLR with the outcome infection.

We included 139 patients. Forty-four infections to report (31.7%), 18 (12.9%) community infections and 26 (18.7%) hospital-acquired infections.Higher NLR values at admission were associated with increased infection risk in univariable and multivariable models - for each unit increase of NLR, infection odds increased 1.29 times (95%CI = 1.09-1.53; p = 0.003), after adjusting for covariates. We performed a classification tree based only on NLR to evaluate the risk of infection. A high-risk group (proportion of patients with infection = 87%) was identified, corresponding to NLR>14; patients with NLR <3.6 presented lower infection risk (17%).Regarding hospital-acquired infection, we were not able to discriminate groups of patients based on classification trees.

NLR is a straightforward approach to attest the individual infection risk on cirrhotic patients. We report NLR cutoffs 3.6 and 14 as optimal for overall infection diagnosing, mainly due to community infection.