Metabolic predictors for mortality among patients treated with long-term clozapine - A longitudinal study

Clozapine is the only antipsychotic compound indicated for refractory-schizophrenia. However, it is associated with emergent metabolic dysregulation and cardiovascular risk which may lead to mortality. In this study we aimed to explore predictors for mortality in a large cohort of schizophrenia patients treated with long-term clozapine, using the electronic medical records of the largest health care provider in Israel. Among 27,929 patients diagnosed with schizophrenia, 1817 were prescribed clozapine during the years 2012-2014. We compared patients who survived (n=1705) and patients who died (n=112) during the 3-year follow-up period. Socio-demographic background, cardiovascular morbidity, medication prescriptions and health-care utilization were compared between groups. Cox proportional hazard models were used to assess the association of variables with survival. Chronic hypertension was found to be the only metabolic factor associated with significant hazard ratio (HR) for mortality (HR: 1.55 95% CI: 1.03-2.34). Moreover, those who died had more prevalent ischemic heart disease (14% vs 3%, p<0.005) as well as more frequent hospitalizations (0.01±0.02 vs 0.11±0.18 average per month, p<0.005), for longer periods (2.22±9.87 vs 20.38±33.76 days per month, p<0.005). Among those who died, less patients received prescriptions of statins for hyperlipidemia (13.7% vs. 52.9% in survivors, p<0.005) and hypoglycemics for diabetes mellitus (16.3% vs. 67.1% in survivors, p<0.005). Inadequate treatment of metabolic syndrome, under chronic clozapine treatment, was found to be an independent predictor for mortality. Adequate rigorous regimen for diagnosis and treatment of metabolic risk factors, especially hyperlipidemia and diabetes mellitus, might lower complications rate and prolong life expectancy among this population.