A retrospective study on laboratory-confirmed acute Chinese medicine poisoning involving aconite in Hong Kong from 2008 to 2020

Background: Territory-wide epidemiological studies of acute Chinese medicine poisoning involving aconite after 2010 are lacking. Objectives: To characterise the latest trends, presumed causes, clinical presentations, healthcare utilisation and patient outcomes of such poisoning cases in Hong Kong. Methods: This was a retrospective observational study of consecutive patients reported to the Hong Kong Poison Information Centre for acute Chinese medicine poisoning by all public emergency departments (EDs) between 1 July 2008 and 30 June 2021. Aconite poisoning was defined by clinical toxicologist verification and laboratory detection of aconitine, related alkaloids or their metabolites in patient biological or herbal remnant samples. We analysed trends using a negative binomial model and characterised presentations using descriptive statistics. Results: In total, 179 episodes of laboratory-confirmed aconite poisoning occurred during the study period. The median annual incidence was 0.22 per 100,000 population (interquartile range 0.11–0.27), with a significant downward trend from 2009 to 2020 (relative risk 0.93, p = 0.037). Fuzi was the most frequently implicated herb (59.2%) and decoction was the most common herbal formulation. Most cases were related to the consumption of Schedule 2 processed aconite. Self-purchase was common. Overdose accounted for 55.5% of cases with available dose information. Supportive treatment remained the mainstay of management. The mortality rate was 1.1%. Conclusions: Despite a decline in incidence, Chinese medicine poisoning with aconite remains a recurring and life-threatening problem in local EDs. Limiting the dose per sale in self-purchase and strengthening public education on appropriate aconite use may further reduce such toxicities.