QT Interval, Antipsychotics and Correlates Among Patients with Schizophrenia: Cross-Sectional Data from the Multicentric Real-World FACE-SZ.

Background: The life expectancy of patients with schizophrenia is reduced, partly due to cardiovascular diseases. Antipsychotics are associated with QT interval prolongation, which is a risk factor for arrhythmia and cardiac arrest. The differences between antipsychotic with regard to QT interval prolongation are not well understood.

Objective: The aim was to compare the QT values associated with different antipsychotics within a real-world population of subjects with clinically stable forms of schizophrenia.

Methods: The FACE-SZ cohort comprises subjects with psychotic disorders, referred to schizophrenia expert cents. QT interval was measured, as well as all treatments (psychotropic and others). The following maintenance treatment for schizophrenia was analysed cross-sectionally: aripiprazole, clozapine, haloperidol, amisulpride, olanzapine, quetiapine, risperidone. Age, sex, smoking status, body mass index, blood potassium levels, and the co-prescription of another QT-prolonging treatment were used as adjustment factors in multivariable linear regression analyses.

Results: Among 792 patients, the mean corrected QT (QTc) interval in the sample of patients under monotherapy was 407 ms. The mean age was 31.7 years, and the majority were male (73.3 %). In comparison to the rest of the sample, clozapine was associated with a longer QTc interval (β = 0.012, 95% CI [0.006-0.018]), while aripiprazole was significantly associated with a shorter QTc interval (β = - 0.010, 95% CI [- 0.016 to - 0.005]). Other antipsychotics were not associated with significant variations of the QTc.

Conclusions: The prescription of antipsychotics should always be accompanied by close monitoring of the QTc interval to prevent the risk of severe cardiac arrhythmia, particularly concerning clozapine.