Absolute Lymphocyte Count as a Predictor of Mortality in Emergency Department Patients with Paraquat Poisoning

Abstract

Background: Paraquat (PQ) is a potent, highly toxic and widely used herbicide. The major medical problems associated with PQ are accidental or suicidal ingestion. There are several prognostic markers of PQ poisoning, with the serum PQ concentration considered to be the best indicator of outcome. However, the measurement of such markers is limited in many hospitals. Objective: The present study was conducted to investigate the association of absolute lymphocyte count (ALC) and the 30-day mortality rate in patients with PQ poisoning. Methods: We performed a retrospective analysis of patients admitted to the emergency department after paraquat poisoning between January 2010 and April 2013. Independent risk factors including ALC for 30-day mortality were determined. The ALC was categorized in quartiles as <= 1700, 1700 to 3200, 3200 to 5000, and >5000. Univariate and multivariate Cox proportional hazard analysis were performed to determine the independent risk factors for mortality. Results: A total of 136 patients were included in the study, and the 30-day mortality was 73.5%. ALC was significantly higher in nonsurvivors than in survivors. The highest ALC quartile (ALC>5000; hazard ratio, 2.58; 95% CI, 1.08-6.21) was associated with increased mortality in multivariate analysis. In addition, old age, lower arterial PaCO2, increased peripheral neutrophil count, and high serum levels of creatinine were associated with mortality. Conclusion: The absolute lymphocyte count is associated with the 30-day mortality rate in patients with paraquat poisoning.