Epidemiological characteristics and outcomes of acute poisoning in Southwest China: a retrospective cohort study with a focus on diquat poisoning

Acute poisoning patterns exhibit substantial regional heterogeneity, but large-scale epidemiological data from Southwest China remain scarce. This study aimed to characterize the epidemiological profile of acute poisoning and to identify high-risk subgroups, with a particular focus on pesticide-related mortality, in Guiyang, Southwest China. We conducted a retrospective cohort study of all patients presenting with acute poisoning to the emergency department of a tertiary hospital in Guiyang between January 2023 and December 2025. Data on demographics, poison categories (including pesticide subtyping), Glasgow Coma Scale (GCS), National Early Warning Score (NEWS), interventions (gastric lavage, intubation, central venous catheterization), and 28-day vital status were extracted from electronic medical records and telephone follow-ups. Descriptive statistics and between-group comparisons (Fisher’s exact test, Mann–Whitney U test) were performed. A total of 2,718 patients were included. The most common poison categories were alcohol (1,197, 44.0%), pharmaceuticals (839, 30.9%), toxic mushrooms/plants (238, 8.8%), and harmful gases (230, 8.5%). Pesticide, insecticide and chemical product poisoning accounted for 162 cases (5.96%) but contributed 14 of the 29 total deaths (48.3%). Among pesticide subtypes, diquat poisoning ( n = 13) resulted in 7 deaths (53.8%), paraquat ( n = 2) in 2 deaths (100%), organophosphates ( n = 30) in 3 deaths (10.0%), and glyphosate ( n = 11) in 2 deaths (18.2%); both glyphosate fatalities presented with severe metabolic acidosis. Harmful gases were the second leading cause of death (8/29, 27.6%), with smoke inhalation having a much higher case-fatality rate (13.3%) than carbon monoxide (2.2%). Alcohol–drug co-ingestion ( n = 64) was associated with zero mortality. Pesticide poisoning required intubation in 12.2% of cases and central venous catheterization in 20.3%, far exceeding rates in other categories. The overall 28-day mortality was 1.07% (29/2,718). Although alcohol and pharmaceuticals dominate the caseload, pesticides—particularly diquat—were the predominant cause of death in this cohort. The 53.8% mortality of diquat poisoning demands urgent public health attention. The zero mortality observed in alcohol–drug co-ingestion warrants further investigation. These findings provide preliminary region-specific evidence for targeted poisoning prevention strategies in Southwest China.