In this article, we evaluated 334 patients to devise a model for prognosis of the outcome in methanol poisoning using hematologic parameters. For this matter, we used the data of the 2020 methanol
poisoning outbreak of Iran.
Methanol poisoning outbreaks usually occur in developing countries, especially regions in which the consumption of alcoholic beverages are legally restricted. In such countries such as Iran people who consume alcohol will use home-made drinks the quality of which is not controlled. These drinks may contain some levels of methanol. Moreover, since patients are often afraid of facing punishments by the governments, they hesitate referring to healthcare centers; consequently, the epidemics may happen. In 2020 Iranian outbreak of methanol poisoning, a contributing factor would have been the shortage of ethanol that was routinely being used for hand sanitizers in the contest of COVID-19 pandemic [12].
Routine risk stratification of patients with methanol poisoning is achieved by the results of blood gas analysis by which patients who experience more severe acidosis, will be more likely to experience morbidity or even death [10]. However, due to resource restriction, blood gas analysis is not available in all healthcare centers; therefore, devising a new prognostic scale for methanol poisoning might be of use, especially in developing regions.
Previous studies have been conducted to find other prognostic factors for lethality in methanol poisoning. In a study by Gulen et al. performed on 67 patients in Turkey, they found that lower Glascow Coma Scale score, and higher lactate were associated with higher mortality. It is reasonable that methanol poisoning patients with lower levels of consciousness have had higher concentrations of formic acid that could enter the central nervous system through the blood brain barrier [13].
We found that patients who will die of methanol poisoning were more likely to have lower blood pressures as a sign of hemodynamic instability. They also had higher levels of creatinine and aspartate aminotransferase. Higher creatinine in deceased patients indicate that acute kidney injury is a predictive factor for mortality that can indicate the need for emergency hemodialysis [14]. Higher aspartate aminotransferase in deceased patients with no significant difference in alanine aminotransferase levels might show that patients with underlying alcoholic liver disease were more likely to die due to methanol poisoning. The findings of our study in this matter are in line with the study of Gulen et al. [13].
In a meta-analysis by Sanaei-Zadeh et al., they found that hyperglycemia was a strong predictive factor for death in methanol poisoning. They speculated that increased blood glucose levels might rise from the increased risk of acute pancreatitis and the increase in the level of stress-related counterregulatory hormones as glucagon and epinephrine [15]. In our study also, the patients who died of methanol poisoning had higher blood glucose levels (P < 0.001). consequently, the findings of our study confirm the previous studies.
The hematologic indices of the patients were put under the spotlight to find a prognostic model for mortality in methanol poisoning. We found that leukocytosis, macrocytosis and elevated lactate dehydrogenase were in favor of more severe status of the patients. Macrocytosis might indicate a long-term alcohol consumption since this condition is associated with larger erythrocytes. Leukocytosis might rise from hemoconcentration and also the acute pancreatitis that was explained by Sanaei-Zadeh et al. [15]. Guillaume et al. also found that patients with higher MCV were more likely to die in the context of methanol poisoning [16].
Finally the correlation between the hematologic indices and the mortality of methanol poisoning was evaluated which showed that serum LDH had the highest direct relationship with mortality. However, no previous studies had been conducted on this matter.