M107 - IDENTIFICATION OF CLINICAL FEATURES THAT PREDICT FUTURE WEIGHT TRAJECTORY IN A NOVEL COHORT OF CLOZAPINE-TREATED PATIENTS

Abstract

There is a lack of genetic and epidemiological studies specific to weight gain among individuals receiving clozapine treatment for established psychosis. Knowing if patients have factors that predispose them to weight gain trajectory or a weight constant trajectory would enable more effective targeting of weight loss programs to avoid problematic weight gain. This study aims to assess the trajectory of weight gain using data routinely collected by Clozapine Therapeutic Monitoring Services in a novel longitudinal cohort of clozapine patients from the United Kingdom and Ireland. We use genetic, clinical and demographic data to determine the influence of these variables on trajectory membership. A total of 3500 individuals had clinical and candidate/proven gene data available. Weight trajectory was calculated from individuals who had at least two weight records over a period of 24 months from the first available record. Trajectories were developed utilising K-Means for Longitudinal data (KML), an algorithm that assigns individuals to a user-defined number of trajectories based on their similarity. There are three distinct trajectories patients take within the first 2 years of clozapine treatment, which are influenced by age, starting weight and clozapine plasma level. Weight gain is more likely to be seen in individuals with younger age, lower plasma levels and lower starting weight. Individuals under the age of 25 with lower starting weight were more likely to be in the weight gain trajectory, whereas older people with higher starting weights were more likely to be in the weight loss trajectory. This could be due to individuals in the weight loss trajectory actively reducing weight after prior weight gain from other antipsychotics. Clozapine plasma levels were also lower in the weight gain trajectory, possibly reflecting incorrect dosage or non-compliance. Clozapine levels were more likely to be in the normal range for individuals in the weight-constant or weight -loss trajectory, reflecting a stable maintenance dosage and increased compliance.