Ziprasidone for Improving Insulin Sensitivity in People With Schizophrenia Who Are at Risk for Diabetes

Phase 4

Completed

Conditions: Insulin Resistance
Metabolic Syndrome X
Schizophrenia

Interventions: Drug: Control
Drug: Switch

Registration Number: NCT00338949

Lead Sponsor: Veterans Medical Research Foundation

Brief Summary: This study will evaluate the effectiveness of ziprasidone treatment versus treatment with a standard atypical antipsychotic drug in improving insulin sensitivity and reducing excess abdominal fat storage in people with schizophrenia who are at risk for diabetes.

Detailed Description: People with schizophrenia often lead more sedentary lifestyles than people without the disease, and they are frequently treated with antipsychotic medications that cause weight gain. Combined, these factors produce an increased risk for metabolic syndrome, which can lead to heart disease and type 2 diabetes. Characteristics of metabolic syndrome include carrying excess weight around the abdominal region; high blood pressure; high blood sugar levels; high levels of fat in the blood; and low levels of HDL cholesterol. Recent studies have shown that certain atypical antipsychotic drugs are relatively weight-neutral. Switching from a drug that promotes weight gain to a weight-neutral medication, such as ziprasidone, may result in significant weight loss. There is insufficient evidence, however, demonstrating the extent of improvement in insulin sensitivity after switching medications. This study will evaluate the effectiveness of ziprasidone treatment versus treatment with a standard atypical antipsychotic drug in improving insulin sensitivity and reducing excess abdominal fat storage in people with schizophrenia who are at risk for diabetes.

Participants in this open label study will currently be undergoing treatment with risperidone or olanzapine at the time of study entry. Upon study entry, they will be randomly assigned to either switch to ziprasidone treatment or remain on their current medications. Both groups will be treated for 26 weeks. Participants will report to the study site for evaluations biweekly until week 10 and then monthly for the duration of the study. The primary outcomes at Week 26 will be: change from baseline in insulin sensitivity, using an intravenous glucose tolerance test; change from baseline in ivisceral fat mass, using a CT scan.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 77

Inclusion Criteria

Diagnosis of schizophrenia or schizoaffective disorder
Currently receiving antipsychotic therapy with risperidone or olanzapine
Overweight

Exclusion Criteria

Diagnosis of diabetes
Hospitalization for schizophrenia or schizoaffective disorder within 90 days prior to study entry
Refractory schizophrenia or schizoaffective disorder
Currently receiving therapy with clozapine
No stable residence and phone number for 90 days prior to study entry
Prior unsuccessful treatment with ziprasidone
Intolerance to ziprasidone

Study & Design

Study Type: INTERVENTIONAL

Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Control	Control	Participants on risperidone or olanzapine who will remain on risperidone or olanzapine and do not switch to ziprasidone
Switch	Switch	Participants who enter on risperidone or olanzapine and switch to ziprasidone

Primary Outcome Measures

Name	Time	Method
Change in Insulin Sensitivity Index From Baseline to Week 26 ((1/mU/L) x 1/Min)	Measured at Baseline and Week 26	As measured by frequently sampled intravenous glucose tolerance testing (units: 1/mU/L) x 1/Min)
Change in Visceral Fat Mass From Baseline to Week 26	Baseline and Week 26	CT measured change in visceral fat mass from baseline to week 26 (mm\^3)

Secondary Outcome Measures