Delta values as a prognostic marker in methanol poisoning: a retrospective cohort study

Abstract

Purpose: The aim of the study was to evaluate the mortality prediction performances of delta bicarbonate, delta anion gap, and delta ratio in methanol poisoning (MP) cases.
 Materials and Methods: This clinical study, which followed a cross-sectional study design, involved patients with MP who were still alive when they initially arrived at the emergency department of a tertiary care hospital. Patients were divided into two groups mortality and non-mortality. Patients who died during treatment and follow-up were assigned to the mortality group, while others were assigned to the non-mortality group. Receiver Operating Characteristic (ROC) analysis was used to determine the cut-off in the diagnostic value measurements of biomarkers predicting mortality. 
 Results: Nine (20%) of the 45 patients in the study died during their follow-up. The two groups showed a significant difference in the averages of pH, bicarbonate (HCO3-), lactate, anion gap, delta anion gap, delta HCO3-, and delta ratio, but not in the averages of partial carbon dioxide pressure (pCO2). In predicting mortality, pH, anion gap, and delta anion gap were found to have outstanding diagnostic power (AUC>0.9), while HCO3-, delta HCO3-, delta ratio were found to have acceptable diagnostic power (AUC: 0.7-0.8). 
 Conclusion: Delta anion gap, delta bicarbonate, and delta ratio can be used as prognostic factors in predicting mortality in MP cases.