A randomized, 12-week study of the effects of extended-release paliperidone (paliperidone ER) and olanzapine on metabolic profile, weight, insulin resistance, and β-cell function in schizophrenic patients

To compare matched paliperidone-ER- and olanzapine-treated schizophrenic patients on measures of glucose and lipid metabolism. Eighty hospitalized patients with schizophrenia (DSM-IV) were randomly assigned to treatment with paliperidone ER or olanzapine for a period of 12 weeks. At baseline and every 4 weeks, we assessed weight, subcutaneous fat, waist and hip circumferences, fasting glucose, insulin, glycohemoglobin A1, cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, and prolactin. We also assessed at every time point body mass index (BMI), homeostasis insulin resistance (HOMA-IR), and homeostasis beta-cell function (HOMA-B). Thirty-three patients randomly assigned to paliperidone ER and 23 patients randomly assigned to olanzapine groups completed the entire 12-week treatment. Within-group analyses showed that fasting measures in both groups increased for weight, BMI, waist circumferences, hip circumference, subcutaneous fat, cholesterol, triglycerides, and prolactin. In contrast, fasting glucose, LDL, and HOMA-B increased during treatment only in the olanzapine group. We also detected significantly different serum prolactin levels at all time point between the paliperidone ER- and olanzapine-treated groups, as well as a statistical trend for HOMA-B to increase more in the olanzapine compared to paliperidone-ER group over the 12 weeks of the trial. We did not detect, however, differential drug effects over the 12 weeks of the trial on fasting measures of BMI, glucose, glycohemoglobin A1, insulin, HDL, LDL, cholesterol, triglyceride, or HOMA-IR. This study reinforces the necessity of regularly monitoring metabolic parameters in patients with schizophrenia taking atypical antipsychotics, including paliperidone ER.