New-onset type-2 diabetes associated with atypical antipsychotic medications

This study compared the one-year incidence of new-onset type-2 diabetes mellitus (DM) and changes in weight in patients with a variety of psychiatric diagnoses prescribed olanzapine, risperidone, or quetiapine, compared to a reference group receiving haloperidol and no other antipsychotic medication.

Data was abstracted from charts of subjects newly initiated and then maintained for one year on olanzapine (n=112), risperidone (n=100), quetiapine (n=100), and haloperidol (n=100). Baseline and one-year DM status, height, and weight were collected, as well as concurrent psychotropic medications, medical and psychiatric comorbidities.

Using a multivariate model, logistic regression identified a significant association between olanzapine (but not other atypical agents) and the development of diabetes compared to haloperidol over the one-year period (odds ratio 8.4, 95% CI 1.8-38.7). Baseline obesity was independently associated with new-onset DM, but only marginally greater weight gain was found among olanzapine users.

The middle-aged American veterans in this study cohort were highly vulnerable to the diabetogenic effects of olanzapine, but a close correlation with weight change was not found. Patients administered olanzapine should receive careful laboratory monitoring for elevated plasma glucose in addition to weight measurement.