Clinical Epidemiology and Predictors of Outcome in Chlorpyrifos Poisoning in Farming and Allied Agricultural Workers in East Godavari, Andhra Pradesh

BACKGROUND: Chlorpyrifos is the ninth most consumed pesticide for agricultural purposes in India. It is a chlorinated organophosphate that also causes poisoning in non-target species such as humans. There is a scarcity of published literature on chlorpyrifos intoxication in the Indian scenario. OBJECTIVE: The objective of the study was to find out the clinical epidemiology and factors influencing the outcome of chlorpyrifos poisoning in the farming and allied agricultural workers. METHODOLOGY: The patient record-based cross-sectional study was carried out on 40 confirmed cases of chlorpyrifos poisoning in a tertiary care teaching hospital in East Godavari district, a predominantly agrarian region in the state of Andhra Pradesh. Clinic-demographic profile, aspects of poisoning, outcome in terms of recovery, death, ventilator support were obtained. Mortality or requirement of ventilator support was classified as a bad outcome. Carlsons’ Co-morbidity Index, Poison Severity Score, and Glasgow Coma Scale score at the time of admission were assessed objectively. The strength of association between the predictor variables and the outcome was represented using the odds ratio. Statistical analysis was performed using Graph Pad Prism 8.0 trial version. RESULTS: Chlorpyrifos poisoning constituted about 10% of pesticide poisoning and 25% of such cases had a poor outcome. The mean age was 44.73 ± 10.76 years, the majority being farmers. Younger age (<40 years), early reporting to hospital, Carlsons’ Co-morbidity Index of less than 8, Glasgow Coma Scale score of more than 12, and Poison severity score of less than 2 were significantly associated with favorable outcome (P < 0.005). During admission, 60% of cases had a plasma pseudocholinesterase level of less than 1000 U/L. Lower plasma pseudocholinesterase was associated with a poor outcome (OR 9.62 CI 4.05-22.84). CONCLUSIONS: Farmers and allied agricultural workers are susceptible to chlorpyrifos intoxication. Along with clinical and laboratory parameters, Carlsons’ Co-morbidity Index, Glasgow Coma Scale score, and Poison severity score at the time of admission are seen as reliable predictors of outcome.