Latent Class Trajectories of Biochemical Parameters and Their Relationship With Risk of Mortality Among Acute Organophosphorus Poisoning Patients

Abstract

Objectives: To determine varying biochemical parameters and their relationship with mortality among organophosphorus poisoning patients through a latent class trajectory analysis.Methods: It was a retrospective cohort study. Patients with organophosphorus poisoning (OP) were admitted to the Intensive Care Unit (ICU) of Ruth Pfau Civil Hospital Karachi from August 2010 to September 2016. A total of 299 OP poisoning patients’ data along with demographic and biochemical parameters were retrieved from medical records. The key outcome measure was in-hospital mortality among acute poisoning patients accounting for gender, age, elapse time since poison ingestion, ICU stay, and biochemical parameters including random blood sugar, creatinine, urea, and electrolytes (sodium, chloride, potassium). The trajectories of parameters were formed using longitudinal latent profile analysis. These trajectories and repeated measures were used as independent variables to determine and compare the risk of mortality by Cox-Proportional-Hazards models. A p-value of <0.05 was considered statistically significant.Results: A total of 299 patients’ data were included with a mean age of 25.4±9.7 years and in-hospital mortality was 13.7%(n=41). In trajectory analysis, patients with high-declining and normal-increasing creatinine, high-remitting, and normal-increasing urea, high-remitting sodium, trajectories observed the highest mortality i.e. 67%(2/3), 75%(6/8), 67%(2/3), 75%(6/8), and 80% (4/5) respectively compared with other trajectories. On multivariable analysis, patients in high-declining creatinine class were sixteen times [HR:15.7,95%CI:3.4-71.6], normal-increasing was fifteen times [HR:15.2,95%CI:4.2-54.6] more likely to die compared with those who had normal consistent creatinine levels. Patients in extremely high-remitting urea trajectory were fifteen times [HR:15.4,95%CI:3.4-69.7], normal-increasing urea trajectory was four times [HR:3.9,95%CI:1.4-11.5] and in high-remitting sodium, the trajectory was six times [HR:5.6,95%C.I:2.0-15.8] more likely to die compared with those who were in normal-consistent trajectories of urea and sodium respectively.Conclusion: Using the latent profile approach, biochemical parameters (creatinine, urea, and sodium levels) were significantly associated with increased risk of mortality among OP poisoning patients.