Surveillance of pesticide poisoning in an East and a West Malaysian hospital: characteristics of pesticide poisoning and the early impact of a national Paraquat ban

Abstract

Background: Previous studies have shown that pesticide bans were associated with reduced fatal pesticide self-poisoning cases in high, and low-and-middle-income countries. We aimed to investigate the characteristics of pesticide poisoning patients admitted to two Malaysian hospitals and the early impact of the national paraquat ban implemented on 1st January 2020 in a culturally heterogenous South-East-Asian upper-middle-income setting. Methods: Data were collected from an East (Bintulu) and a West (Ipoh) Malaysian hospital medical records in 2015–2021 and 2018–2021, respectively. Logistic regression analyses were conducted to investigate the association of aspects such as socio-demographic and clinical characteristics, paraquat ban with the types of pesticides involved (paraquat versus non-paraquat versus unknown) ,and the outcomes (fatal versus non-fatal). Results: From the study sample of 212 pesticide poisoning patients aged 15 years or above, the majority were self-poisoning cases (75.5%) with a disproportionate over-representation of Indian ethnic minority (44.8%). Most pesticide poisoning cases had socio-environmental stressors (62.30%). The commonest stressors were domestic interpersonal conflicts (61.36%). 42.15% of pesticide poisoning survivors had a psychiatric diagnosis. Paraquat poisoning accounted for 31.6% of all patients and 66.7% of fatalities. Case fatality was positively associated with male gender, current suicidal intent, and paraquat poisoning. After the paraquat ban, the proportion of pesticide poisoning cases using paraquat decreased from 35.8 to 24.0%, and the overall case-fatality dropped slightly from 21.2 to 17.3%. Conclusions: Socio-environmental stressors in specific domestic interpersonal conflicts, seemed more prominent in pesticide poisoning compared to psychiatric diagnosis. Paraquat accounted for the majority of pesticide-associated deaths occurring in hospitals in the study areas. There was preliminary evidence that the 2020 paraquat ban led to a fall in case fatality from pesticide poisoning.