Role of the Acute Physiology and Chronic Health Evaluation II (APACHE II) Score in Predicting Outcomes in Paraquat Poisoning

Background and aimsParaquat poisoning is associated with high mortality and progressive multiorgan dysfunction.Early prognostic assessment remains difficult where toxin-specific assays are unavailable.This study evaluated the role of the Acute Physiology and Chronic Health Evaluation II (APACHE II) score in predicting mortality in patients with paraquat poisoning. Patients and methodsThis prospective observational study included 80 patients with confirmed paraquat poisoning who were admitted to a tertiary care hospital.Demographic, clinical, and laboratory data; organ dysfunction; organ support; estimated ingested dose; and APACHE II scores within the first 24 hours of ICU admission were recorded.The primary outcome was in-hospital mortality.Logistic regression was used to identify factors associated with mortality, and receiver operating characteristic (ROC) analysis assessed the discriminatory ability of APACHE II. ResultsOf 80 patients, 27 (33.8%)survived and 53 (66.2%) died.Renal dysfunction was the most frequent organ abnormality (75.0%), followed by respiratory (63.8%) and hepatic dysfunction (62.5%).Mortality increased with estimated ingested dose, from 21.1% for <20 mL to 62.5% for 20-50 mL and 91.4% for >50 mL (p < 0.001).PaO 2 was significantly lower among non-survivors than survivors (median 86 vs. 88 mmHg, p = 0.034).Median APACHE II scores were 15 in survivors and 16 in non-survivors (p = 0.205).APACHE II was not significantly associated with mortality on univariable analysis (OR 1.11, 95% CI 0.99-1.24;p = 0.080), and ROC analysis showed poor discrimination (AUC 0.587, 95% CI 0.461-0.712).In a sensitivity analysis excluding four patients with unknown or difficult-to-interpret dose estimates, recorded estimated dose showed greater discriminatory performance than APACHE II. ConclusionAPACHE II demonstrated poor discrimination for in-hospital mortality in this cohort of patients with paraquat poisoning (AUC 0.587, 95% CI 0.461-0.712)and was not significantly associated with mortality on univariable analysis.Mortality increased with estimated paraquat dose, while lower PaO 2 was associated with mortality on univariable analysis.In the sensitivity analysis, recorded estimated dose showed greater discriminatory performance than APACHE II in the restricted patient subset.These findings indicate that APACHE II had limited discriminatory ability in the present cohort and should not be used as a stand-alone predictor of mortality.As paraquat poisoning may involve progressive organ dysfunction, a single APACHE II assessment within the first 24 hours may not fully reflect the subsequent clinical course.Future studies should evaluate whether serial APACHE II assessments provide additional prognostic information beyond the initial score.Larger prospective multicenter studies are needed to validate clinically useful prognostic models.