OGTT-Defined Insulin Resistance in Adults With Schizophrenia and Schizoaffective Disorder: Comparing Clozapine versus other Antipsychotics
C. Esme, E. Van Assche, C. Hohoff, S. Claes, M. De Hert, B. BauneIntroduction
Antipsychotic-associated metabolic dysfunction and weight gain is a significant concern, particularly raised in the context of clozapin treatment. Insulin resistance (IR) is often named as a facilitator in this relationship. Evidence from oral glucose tolerance tests (OGTTs) to compare clozapine with other antipsychotics is limited and inconsistent. The present study compares IR by OGTT between clozapine-treated patients and non-clozapine-treated patients, with a particular focus on the role of duration of illness (DOI). We expect an increased risk for insulin resistance by OGTT in the patient group receiving clozapine, compared to other antipsychotics.
Objectives
Compare insuline resistance between clozapine and non-clozapine users, taking duration of illness into account.
Methods
A total of 379 individuals with a diagnosis of schizophrenia or schizoaffective disorder (Mage= 34.05; %67.28 Men) were included in our analysis. Sixty-seven patients (Mage= 35.68; 68.66% men) were treated with clozapine at the time of investigation. The other patients (Mage= 33.70; 66.99% men) were treated with risperidon (N = 82), Amisulprid (N = 34), Ariprazol (N = 7), Olanzapine (N = 113), Quetiapine (N = 36), 1st generation antipsychotics (N = 26), or no antipsychotic (N = 14). Insulin resistance was measured with OGTT (MIR= 2.62; SD = 2.12). Mean duration of illness (DOI) was 10.70 years (SD = 9.79). Analyses were performed in R using Anova and linear regression. Analyses were corrected for biological sex and age.
Results
Following adjustment for DOI, age and sex, insulin resistance as measured with OGTT was not statistically significant between patients treated with clozapine and patients treated with other antipsychotics (F(1, 360) = 1.71; p > 0.10). DOI was not associated with IR either (p > 0.10), however clozapine treatment was associated with DOI after adjustment for age and sex (F(1, 362)= 0.146; p< 0.001), with a longer DOI for patients receiving Clozapine.Stratification using a DOI-by-treatment group analysis also did not affect the risk for IR significantly either (p > 0.10).
Conclusions
Our results indicated that clozapine exposure and duration of illness—either independently or in interaction—were not associated with a an elevated risk of OGTT-defined insulin resistance, in comparison to other antipsychotics. The observed difference in illness duration, with a longer duration of illness among clozapine users compared to other patients, is consistent with clozapine’s frequent use as a third-line treatment. Contrary to our initial hypothesis, our data did not demonstrate a higher risk for insulin resistance in patients treated with clozapine, nor in those with a prolonged history of disease.
Disclosure of Interest
None Declared