Association between the glucose-to-lymphocyte ratio and prognosis in COVID-19 patients

The coronavirus disease 2019 (COVID-19) pandemic has transitioned into an endemic stage and is no longer classified as a public health emergency of international concern. Nevertheless, the persistent emergence of novel variants with enhanced transmissibility and immune evasion potential suggests that the disease burden associated with COVID-19 remains substantial. This retrospective cohort enrolled 235 hospitalized COVID-19 patients infected during the Omicron BA.5 and BF.7 wave from December 29, 2022 to January 15, 2023. The prognostic value of biomarkers based on combined fasting glucose and lymphocyte counts in patients with COVID-19 has not been fully clarified. We measured inflammatory markers, the metabolic marker, and T-cell immune parameters to validate our a priori hypothesis that glucose-to-lymphocyte ratio (GLR) mirrors concurrent inflammation. This study aimed to explore the associations between GLR and disease severity as well as clinical outcomes among hospitalized COVID-19 patients.

We retrospectively analyzed a cohort of 235 individuals with COVID-19 to explore the prognostic value of GLR levels at diagnosis. All patients were followed up until the unified cutoff date of February 18, 2023, with all-cause mortality set as the primary endpoint. Two separate grouping methods were used: GLR stratification for evaluating its independent predictive ability, and severity grouping (mild-to-moderate vs severe) as clinical reference. The two groups only partially overlapped, so high GLR is not equivalent to severe illness. Patients were stratified into high GLR and low GLR groups. Overall survival (OS) was estimated via the Kaplan-Meier method and compared using the log-rank test.

Our findings revealed that GLR levels were significantly higher in severe patients than in mild-to-moderate patients. Meanwhile, beta2-microglobulin (β2-MG), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and interleukin-10 (IL-10) were significantly elevated in the high GLR group, whereas apolipoprotein A1 (ApoA1), CD3 absolute value, CD4 absolute value, and CD8 absolute value were significantly lower. Furthermore, patients with high GLR levels exhibited significantly shorter OS (P < 0.0001). An elevated GLR level (> 14.42) was found to be an independent, adverse prognostic factor for OS in Omicron patients, according to multivariate Cox proportional hazards regression analysis (P = 0.003).

Our data confirmed that GLR levels at initial diagnosis were significantly correlated with disease severity and prognosis in patients with COVID-19. As an easily calculated metabolic-immune indicator, GLR acts as a promising complementary candidate biomarker for mortality risk stratification in Omicron COVID-19 patients; further independent external validation is required before its routine clinical application.