White Blood Cell Count as a Prognostic and Mechanistic Mediator in Acute Diquat Poisoning: A Retrospective Cohort Study Enabling Risk Stratification for Resource-Limited Settings

BackgroundDiquat poisoning is associated with high mortality, and accurate prognostication remains challenging in resource-limited settings. This retrospective cohort study evaluated white blood cell count (WBC) as both a prognostic biomarker and mechanistic mediator in acute diquat poisoning.MethodsThis retrospective cohort included 134 patients with acute diquat poisoning (2016-2025). WBC was analyzed continuously and categorically (median and ROC-derived cut-offs). Multivariable regression, subgroup, and mediation analyses were performed.ResultsThe high-WBC group (≥ 17.11 × 10⁹/L) had significantly higher mortality (64.3% vs. 7.8%, P < 0.001). After adjustment, patients with WBC ≥ 17.235 × 10⁹/L had a 3.43-fold higher mortality risk (95%CI:1.37 - 8.60). Each 1 × 10⁹/L WBC increase predicted a 6% mortality risk rise (adjusted OR = 1.06, 95%CI:1.01 - 1.12). WBC mediated 15.5% (P = 0.02) of plasma diquat's total lethal effect. ROC analysis showed WBC had an AUC of 0.724 (95%CI:63.5% - 81.2%) at the optimal cut-off of 17.235 × 10⁹/L, comparable to plasma diquat concentration's AUC of 0.817 (95%CI:74.4% - 88.9%).ConclusionsWBC serves as both a continuous predictor and triage tool at 17.235 × 10⁹/L, providing a practical risk-stratification framework for settings lacking toxicological testing.