Admission neutrophil-to-lymphocyte ratio to predict mortality in burn patients: a meta-analysis

Background: The neutrophil-to-lymphocyte ratio (NLR) proves to be a convenient and cost-effective marker with studies showing that a high NLR can serve as a mortality indicator in burn cases. We conducted a meta-analysis aiming to explore whether on-admission NLR values could serve as predictors of mortality in burn patients.

Methods: PubMed, Web of Science, Scopus and Embase were searched from inception until January 2024. We included all studies investigating burn patients that contain information on the NLR value at the time of hospital admission and mortality outcomes. The studies were critically appraised using the NIH Quality Assessment Tool.

Results: Nine studies fulfilled our criteria with a total population of 1837 participants, including 1526 survivor Burn patients and 311 non-survivor Burn patients. The overall mean difference measured by random model showed a significant increase in NLR by 5.06 (95% CI 3.42, 6.68) p ≤ 0.001 for the non-survivor group over the survivors group with heterogeneity I² = 67.33%, p ≤ 0.001. A meta-regression was done to investigate the potential source of heterogeneity among studies. The results showed that age (p = 0.394), gender (p = 0.164), and sample size (p = 0.099) did not contribute to the source of heterogeneity, however, the burn surface area contributed significantly (p = 0.002). A leave-one-out meta-analysis was done, showing that omitting Le Qui et al., leads to significantly decrease the heterogeneity to be I² = 2.73%. Meta-regression repeated to assess the burn surface area again to be found noncontributing (p = 0.404).

Conclusions: Our findings support that elevated NLR values can serve as a mortality indicator in burn cases. This will have a great clinical impact by aiding in stratifying the burn patients on admission.