Background Organophosphorus (OP) poisoning is a leading cause of mortality due to self-harm in Asian countries, including India. Red blood cell cholinesterase (RBC-ChE) and serum cholinesterase (serum-ChE) levels are used for predicting outcomes. There is a paucity of literature studying the RBC-ChE levels in OP poisoning and comparing it with the serum-ChE levels.

Methods This is a longitudinal study assessing the outcome in OP poisoning patients using the RBC-ChE and serum-ChE levels. Both enzyme levels are compared and correlated for adult patients presenting within 24 hours of consumption of the OP compound. Sensitivity and specificity are measured.

Results Of the 99 OP poisoning patients included, 20 patients did not survive, and 23 patients required ventilatory support. At admission, RBC-ChE (median, interquartile range [IQR]) was significantly different between survivors (45.2 [30.5–60] U/g Hb) and nonsurvivors (6.3 [4.2–13.4] U/g Hb), while serum-ChE (median, IQR) was not statistically different (p = 0.061) between survivors (350 [247–670]) and nonsurvivors (290 [182–415.8]). Similarly, RBC-ChE was significantly different between patients requiring a ventilator and those not requiring a ventilator (6.8 vs. 44.2 U/g Hb), whereas the serum-ChE values measured on admission were not significantly different for patients requiring a ventilator versus those not requiring a ventilator (290 vs. 348 U/L; p = 0.119). At the cutoff of 20 U/g Hb, RBC-ChE had 90.5% sensitivity and 91% specificity in predicting mortality. Kaplan–Meier survival showed the probability of survival decreased to nearly 50% if the time to reach the hospital was ≥4 hours.

Conclusion RBC-ChE was superior in predicting outcomes in OP poisoning patients compared with serum-ChE measured on the day of admission.

The study was conducted in accordance with the ethical standards as laid down in the Declaration of Helsinki and its later amendments or comparable ethical standards.

The study was approved by the Institutional Ethics Committee of S.C.B. Medical College and Hospital, Cuttack, vide IEC/IRB no. 402/14.10.2020.

Informed consent was obtained from each participant in written form in the local Odia language. In a situation where the participant could not provide consent, informed consent was obtained from their first-degree relative/legal guardian.

S.K. contributed to the conception, data collection, and drafting of the manuscript. N.R.M. contributed to the study design and review of literature. B.P. contributed to review of the literature and revising the manuscript. R.R. contributed to biochemical measurements and review of the manuscript. A.C. contributed to statistical analysis, interpretation of data, and preparation of tables and figures. S.P. contributed to review of the manuscript. P.K.R. was responsible for reference management. B.D. provided assistance during patient interaction and contributed to review of the manuscript. B.R.P. contributed to review of the manuscript and the references. P.K.T. contributed to conception, interpretation of data, and review of the manuscript.

Received: 25 May 2023

Accepted: 27 July 2023

Article published online:
28 September 2023

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