Effects of switching from olanzapine to risperidone on the prevalence of the metabolic syndrome in overweight or obese patients with schizophrenia or schizoaffective disorder: analysis of a multicenter, rater-blinded, open-label study.

BACKGROUND: A major contributor to mortality inpatients with schizophrenia or schizoaffective disorder is cardiovascular disease, an important risk factor for which is the cluster of clinical abnormalities that define the metabolic syndrome (eg, abdominal/visceral obesity, hypertriglyceridemia, impaired glucose tolerance).

OBJECTIVE: The aim of this article was to examine the effects of switching from the antipsychotic olanzapine to risperidone on the prevalence of the metabolic syndrome in high-risk overweight or obese patients with schizophrenia or schizoaffective disorder.

METHODS: This post hoc analysis was based on data from a previous 2-phase, 20-week, multicenter (19 US sites), rater-blinded, open-label study. High-risk overweight or obese (body mass index [BMI], >26 kg/m(2)) patients aged 18 to 65 years with schizophrenia or schizoaffective disorder whose treatment was switched from olanzapine to risperidone were enrolled. Patients who entered the phase 1 switch from olanzapine to risperidone (6 weeks) and the phase 2 extension (14 weeks) were included in the assessment. The primary end point was the difference from baseline in the prevalence of the metabolic syndrome at week 20, determined using measurements of weight, BMI, waist circumference, and systolic and diastolic blood pressure (SBP/DBP).

RESULTS: Baseline assessments for the metabolic syndrome were available from 121 of 123 patients recruited for phase 1 of the study (61 men, 60 women; mean [SD] age, 41.1 [10.2] years; mean [SD] BMI, 33.9 [6.9] kg/m(2)); 71 patients entered phase 2 (29 men, 42 women; mean [SD] age, 40.2 [10.3] years; mean [SD] BMI, 35.1 [7.3] kg/m(2)), of whom 39 (54.9%) ere diagnosed with schizophrenia, and 32 (45.1%) with schizoaffective disorder. The metabolic syndrome was identified in 63 (52.1%) patients at study entry. In the 71 patients with data available from baseline and week 20 (using the last observation carried forward method), the prevalence of the metabolic syndrome was reduced from 38 (53.5%) patients at baseline to 26 (36.6%) at study end (McNemar chi(2) = 8.0, P < 0.005). Significant improvements at study end were seen in mean weight (P = 0.031), BMI (P = 0.002), waist circumference (P = 0.003), SBP (P = 0.006), and DBP (P = 0.010). There was no significant difference in the reduction in the prevalence of the metabolic syndrome between patients who did or did not receive the behavioral therapy for weight loss.

CONCLUSIONS: In this post hoc analysis of switching from the antipsychotic olanzapine to risperidone on the prevalence of the metabolic syndrome in high-risk overweight or obese patients with schizophrenia or schizoaffective disorder, the metabolic syndrome was highly prevalent at baseline. Switching from olanza- pine to risperidone was associated with a significant reduction in this prevalence.