Michael J. Sernyak, MD; Barbara Gulanski, MD; Douglas L. Leslie, PhD; and Robert Rosenheck, MD
Background: Clozapine has been demonstrated to
be superior to typical neuroleptics in reducing refractory
symptoms in patients with schizophrenia, but it has also been
associated with hyperglycemia and diabetes mellitus. This study
was designed to investigate the proportion of undiagnosed
impaired fasting glucose and diabetes mellitus in patients
prescribed clozapine at 8 Department of Veterans Affairs (VA)
medical centers.
Method: All patients diagnosed by the VA
in New England with ICD-9 schizophrenia from Oct. 1, 1999, to
Sept. 30, 2000, who received a prescription for clozapine were
identified, and an attempt was made to obtain a fasting plasma
glucose (FPG) test. All patients were also characterized as to
whether they were diagnosed as diabetic prior to the screening
FPG. Patients not previously diagnosed as diabetic were divided
into 2 groups: normal FPG (< 110 mg/dL) and elevated FPG
(>= 110 mg/dL). Clinical and sociodemographic characteristics
of the 2 groups were compared using chi-square and t tests.
Results: Overall, 121 patients were not
previously diagnosed as diabetic and received an FPG.
Ninety-three (77%) had a normal FPG, and 28 (23%) had an elevated
plasma glucose-including 17% with impaired fasting glucose and 6%
with diabetes. Patients with hyperglycemia were significantly
older (p = .007) and more commonly codiagnosed with bipolar
disorder (p = .04).
Conclusion: Hyperglycemia was common in patients
receiving clozapine who had not been previously diagnosed as
diabetic. These patients should be considered a group at high
risk to develop diabetes mellitus and deserve both close
monitoring and early intervention at the first sign of the onset
of either diabetes or impaired glucose tolerance.
J Clin Psychiatry 2003;64(5):605-608
© Copyright 2003 Physicians Postgraduate Press, Inc.