The epidemiology of household rodenticides poisoning in Hong Kong and its risk factors for developing coagulopathy

Objective: To (1) describe the epidemiology of household rodenticides poisoning in Hong Kong, (2) evaluate the proportion of patients who have develop coagulopathy after rodenticide poisoning, (3) identify the risk factors for developing coagulopathy in rodenticide poisoning. Design: Case series study. Setting: Sixteen accident and emergency departments in Hong Kong. Patients: Patients with household rodenticide ingestion who presented to accident and emergency departments during the period from July 2008 to February 2012. Results: 110 patients were reported to have rodenticide exposure during the study period. Eighty-seven patients were included in the final analysis. The mean age was 40.1 and the male-to-female ratio was 1.29:1 (49:38). Most patients (91%) took the rodenticide intentionally. Sixty-nine patients (79%) exposed to anticoagulants type of rodenticide based on history or laboratory findings. The ingredient of the rodenticide ingested in 18 patients (21%) was untraceable. The only clinically significant presentation reported after rodenticide exposure was coagulopathy. Thirty-one patients (36%) developed coagulopathy with an international normalised ratio greater or equal to 1.3. Clinical significant bleeding was only observed in one patient. Presence of coagulopathy in rodenticide poisoning was significantly associated with older patient, intentional ingestion, ingestion of warfarin, ingestion of more than one pack and presence of co-ingestion. Multiple logistic regression analysis showed that only two factors were independent predictor of coagulopathy: Ingestion of warfarin rodenticide (p=0.001, odds ratio [OR]=18.20, 95% confidence interval [CI]=3.44-96.42), and ingestion of more than one pack of rodenticide (p=0.02, OR=10.01, 95% CI=1.43-69.87). Conclusions: Clinically significant household rodenticide poisoning in Hong Kong is solely related to ingestion of anticoagulant type of rodenticide. Patients who have ingested warfarin rodenticide and higher ingestion dose are more likely in developing coagulopathy.