Predictive value of NLR and PLR for immune-related adverse events: a systematic review and meta-analysis

Currently, there is a lack of affordable and accessible indicators that can accurately predict immune-related adverse events (irAEs) resulting from the use of immune checkpoint inhibitors (ICIs). In order to address this knowledge gap, our study explore the potential predictive value of two ratios, namely the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR), for irAEs in cancer patients.

A systematic search was performed in PubMed, Embase, and the Cochrane library. Studies involving NLR or PLR with irAEs were included. Quality and risk of bias of the selected studies were assessed. Forest plots were created based on Cox model analysis. Random effects meta-analyses were conducted to estimate odds ratio (OR) and its 95% confidence interval (CI).

After screening 594 studies, a total of 7 eligible studies with 1068 cancer patients were included. Analysis based on Cox regression showed that low neutrophil-lymphocyte ratio (L-NLR) (OR = 3.02, 95% CI 1.51 to 6.05, P = 0.002) and low platelet-lymphocyte ratio (L-PLR) (OR = 1.83, 95% CI 1.21 to 2.76, P = 0.004) were associated with irAEs. In the subgroup analysis of cut-off value, when the NLR cut-off value was 3, irAEs was significantly correlated with NLR (OR = 2.63, 95% CI 1.63 to 4.26, P < 0.001).

Both L-NLR and L-PLR have been found to be significantly associated with irAEs. Consequently, patients identified as being at a higher risk for irAEs should be subjected to more diligent monitoring and close observation.