Association of the neutrophil-lymphocyte ratio with outcome in sick foals

The ratio of the two predominant white blood cells was a very good predictor of the survivability of sick newborn foals.
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Association of the neutrophil-lymphocyte ratio with outcome in sick hospitalized neonatal foals
J Vet Intern Med. 2024 Mar-Apr;38(2):1196-1206. doi: 10.1111/jvim.16995. Epub 2024 Jan 29.
Authors
Amanda N Samuels 1 , Ahmed M Kamr 1 , Stephen M Reed 2 , Nathan M Slovis 3 , Laura D Hostnik 1 , Teresa A Burns 1 , Ramiro E Toribio 1
Affiliations

1 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.
2 Rood and Riddle Equine Hospital, Lexington, Kentucky, USA.
3 Hagyard Equine Medical Institute, Lexington, Kentucky, USA.

PMID: 38284437
PMCID: PMC10937482
DOI: 10.1111/jvim.16995

Free PMC article
Abstract

Background: The neutrophil-lymphocyte ratio (NLR) in human medicine is an objective biomarker that reflects prognosis. The NLR as an independent biomarker to help predict nonsurvival in hospitalized neonatal foals has not been thoroughly interrogated.

Objectives/hypothesis: Retrospectively evaluate if the NLR at admission is associated with nonsurvival in sick hospitalized foals <4 days old. We hypothesized that a lower NLR will be associated with nonsurvival.

Animals: One thousand one hundred ninety-six client-owned foals <4 days old of any breed and sex: 993 hospitalized foals and 203 healthy foals.

Methods: Retrospective multicenter study. Medical records of foals presenting to 3 equine referral hospitals were reviewed. Foals were included if they had complete CBCs, sepsis scores, and outcome data. The NLR was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count. Data were analyzed by nonparametric methods and univariate analysis.

Results: Of the 993 sick hospitalized foals, 686 were sick nonseptic and 307 were septic. The median NLR was lower in sick hospitalized foals (median [95% confidence interval], 3.55 [0.5-13.9]) compared with healthy foals (6.61 [3.06-18.1]). Septic foals had the lowest NLR (2.00 [0.20-9.71]). The NLR was lower in nonsurviving (1.97 [1.67-2.45]) compared with surviving foals (4.10 [3.76-4.33]). Nonsurviving septic foals had the lowest NLR (1.47 [1.70-3.01]). Foals with a NLR of <3.06 or <1.6 at admission had odds ratio of 3.21 (2.24-4.29) and 4.03 (2.86-5.67) for nonsurvival, respectively.

Conclusions and clinical importance: A NLR < 3.06 at admission in sick hospitalized foals is readily available and clinically useful variable to provide prognostic information. Keywords: biomarker; equine neonate; hematology; immunology; sepsis. © 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.