Comparison of metabolic and prolactin variables from a six-month randomised trial of olanzapine and quetiapine in schizophrenia

Abstract

Schizophrenia patients have a potential increased risk of metabolic dysregulation during antipsychotic treatments. Our objective was to compare changes in prolactin and metabolic variables (glucose, lipids and weight) as a post-hoc analysis from a six-month, randomised, controlled study of olanzapine (OLZ, n = 171; 10—20 mg/day) or quetiapine (QUE, n = 175; 300—700 mg/day). No statistically significant treatment group differences for baseline to endpoint mean changes in body mass index (P = 0.209) or weight (P = 0.250) were observed. There was a greater incidence of clinically significant weight gain (defined as ≥7% increase from baseline) in OLZ (19.2%) compared to QUE (13.2%)—treated patients (P = 0.181). No statistically significant treatment group differences for lipids and glucose variables, either as mean change from baseline to endpoint or treatment-emergent (TE) categorical changes were found (P ≥ 0.05). Incidence rates for TE diabetes were similar between treatment groups 2.5% (n = 4) in the OLZ-treatment group and 1.3% (n = 2) in the QUE-treatment group (P = 0.685). Hyperprolactinaemia was present at baseline in many patients (OLZ 32.9%; QUE 31.4%), but after 2 weeks of treatment prolactin values had reverted to normal for nearly all patients (OLZ 100%; QUE 99.4%). There were no significant treatment differences in any variable between cohorts.