Testing for Antipsychotic-Induced Diabetes Mellitus

Dear Editor:

McIntyre and others (1) reported an increased risk of developing diabetes mellitus with atypical antipsychotics. Their review article reported Zoler’s findings of antipsychotic-induced diabetes mellitus of 15.5% for clozapine, 11% for olanzapine, and 6% for risperidone, compared with the lifetime age-adjusted diabetes mellitus prevalence of 5% to 7% in the general population (2). Their review also noted the fact that a family history of diabetes mellitus and weight gain are risk factors for the development of diabetes mellitus. Goldstein reported the onset of de novo diabetes mellitus between 5 weeks and 68 weeks (mean 26 weeks) after treatment initiation with clozapine (3).

In light of these findings, I would like to suggest an early detection maneuver that could easily be applied to clozapine patients. The addition of a blood glucose test to the first 26 weeks of clozapine patients’ weekly blood work would most likely pick up early-developing diabetes mellitus. The cost of a blood glucose determination in our lab is $1.18, compared with the cost of a complete blood count and differential at $14.39. I recently had a patient admitted in diabetic ketoacidosis that resulted in several weeks’ hospitalization. This probably could have been prevented by such a system.

References

Barbara J Kane, MD, FRCP
Prince George, British Columbia