Hematological inflammation coefficients as predictors of QT interval prolongation during clozapine therapy

Background. According to the literature, more than two thirds of patients with schizophrenia die from cardiovascular dis-eases. Among the agents of drug therapy for schizophrenia, preference is given to antipsychotic drugs. Prolongation of the QT interval as a prognostic marker of fatal rhythm disturbances is one of the most significant adverse reactions associated with the use of antipsychotics due to the high risk of life-threatening arrhythmias. Objective: to determine the relationship between clinical and laboratory parameters and prolongation of the QTc interval in patients with schizophrenia taking clozapine. Mate-rials and Methods. The study included 129 inpatients with an established diagnosis according to ICD-10: paranoid schizo-phrenia (F20.0), receiving clozapine therapy. Prolongation of the QTc interval was defined as a difference of ≥30 ms between the QTc interval values of the repeated and baseline electrocardiograms. Results. An increased risk of QTc interval prolonga-tion was found with a statistically significant higher frequency in women (OR 0.37; 95% CI 0.163-0.842; p=0.016), with in-creasing patient age (p=0.007), high-density lipoprotein (p=0.014) and platelet (p=0.008) levels, systemic immune inflamma-tion index (p=0.018) and a decrease in the monocyte to high-density lipoprotein ratio (p=0.002). However, there was no statis-tically significant relationship between QTc interval prolongation, the number of concomitantly administered antipsychotics and their cumulative dose. Discussion. In addition to inhibition of potassium channels hERG (Kv11.1), clozapine can cause inflammatory damage to the myocardium and lead to its irreversible remodeling, diagnosed as myocarditis and dilated cardio-myopathy. However, despite the potentially fatal cardiotoxicity, clinical guidelines and instructions for the use of clozapine do not provide clear instructions on monitoring the electrocardiogram and possible predictors of life-threatening arrhythmias when taking this antipsychotic. Conclusion. Our study showed an increased risk of prolongation of the QTc interval in women, with increasing patient age, high-density lipoprotein and platelet levels, systemic immune inflammation index and a decrease in monocytes to high-density lipoproteins.