Patients with bipolar disorder are at risk of obesity, metabolic syndrome and diabetes mellitus. Little was known about the association of clinical characteristics of bipolar disorder and diabetes mellitus.

Investigate the clinical characteristics of patients with bipolar disorder and diabetes mellitus.

Identify the risk factors of medical comorbidity.

Patients suffering from bipolar disorder, according to DSM-IV classification, with and without diabetes mellitus were retrieved from computer database in a university teaching hospital psychiatric outpatient clinic. Patients with diabetes mellitus were compared with patients without diabetes mellitus after matching with sex and age.

One hundred and fifty patients with bipolar disorder (30 with diabetes mellitus and 120 without diabetes mellitus) were collected. All patients were Chinese and 86.7% were female. For patients with and without diabetes mellitus, the mean (SD) age were 49.9 (9.3) years and 49.4 (8.9) years respectively. Their mean (SD) duration of mental illness were 18.1 (10.9) years and 16.8 (10.6) years and the mean number of admissions were 3.4 (4.2) and 3.2 (4.3) for patients with and without diabetes mellitus respectively. The use of antipsychotics and mood stabilizer were similar between patients with and without diabetes mellitus. Hypertension and dyslipidemia were statistically significant factors associated with diabetes mellitus among patients with bipolar disorder.

Hypertension and dyslipidemia are associated with diabetes mellitus among Chinese patients with bipolar disorder. Psychiatrists should be alerted to screen and monitor for hypertension, dyslipidemia and diabetes mellitus among patients with bipolar disorder.