External validation of the prognostic index in acute paraquat poisoning.

ABSTRACT

OBJECTIVE: Some studies have evaluated the prognostic indicators associated with acute paraquat (PQ) poisoning. In this study, we externally validated the Yamaguchi index, which showed a good prognostic relevance in predicting the outcome of PQ poisoning. METHODS: A retrospective analysis of 297 patients was performed. The Yamaguchi index was calculated using the following equation Eq1 = (K(+) × HCO3(-))/(Creatinine × 0.088)(mEq/L) against time from PQ ingestion (T). The patients were divided into three groups group A Eq1 > 1500 - 399 × log T, group B 930 - 399 × log T < Eq1 ≤ 1500 - 399 × log T, and group C Eq1 ≤ 930 - 399 × log T). RESULTS: The overall mortality rate was 65.3% (194 of 297). The mortality rates of the three groups stratified by the Yamaguchi index were 7.1% (2 of 28), 22.4% (15 of 67), and 87.6% (177 of 202). The area under the receiver-operating characteristic curve for predicting mortality from the external validation of the Yamaguchi index was 0.842 (95% confidence interval 0.795-0.882). CONCLUSION: The Yamaguchi index is a reliable prognostic factor and could be helpful in predicting mortality due to PQ poisoning.