Neutrophil–Lymphocyte Ratio Reflects Inflammation-Related Hypoalbuminemia Rather Than Body Composition Phenotype in Hospitalized Adults

Abstract

Introduction: The neutrophil-lymphocyte ratio (NLR) is a simple inflammatory biomarker with potential applications in nutritional assessment. However, its relationship with both visceral proteins and body-composition phenotypes in heterogenous hospitalized populations is unclear.

Objectives: To examine the associations between NLR and serum albumin and to determine whether NLR predicts a low-muscle body-composition phenotype measured by bioelectrical impedance analysis (BIA).

Methods: Cross-sectional study of 120 adults admitted to Hasanuddin University Hospital (median age 44 years; 55% female). NLR was calculated from admission complete blood counts. Physique rating was measured by bioelectrical impedance (Tanita BC-730). Serum albumin was available for 104 patients. We used Spearman correlation and multivariable linear regression adjusted for age, sex, and primary diagnosis to examine associations with albumin; logistic regression tested whether log-transformed NLR predicted a BIA-defined low-muscle phenotype.

Results: Median NLR was 3.75 (IQR 1.92–7.28). Median serum albumin was 34 g/L (IQR 26.3–38.0 g/L); 51% had hypoalbuminemia. NLR correlated negatively with albumin (rho = −0.359, p < 0.001). In adjusted regression, each one-unit NLR increase was associated with a −0.42 g/L change in albumin (p = 0.001). NLR did not differ between physique rating groups, and log-NLR did not predict low-muscle phenotype.

Conclusions: In hospitalized adults, elevated NLR is independently associated with lower serum albumin levels but was not associated with a BIA-defined low-muscle phenotype after adjustment.  These findings suggest that NLR primarily reflects acute inflammation-related nutritional alterations rather than chronic body-composition phenotypes in hospitalized adults.