Diabetes mellitus in patients with chronic bipolar disorder: prevalence, clinical correlates and relationship with homocysteine.

Comorbid diabetes mellitus in patients with bipolar disorder may contribute to increased morbidity and mortality. To determine the prevalence of diabetes mellitus in bipolar disorder patients and its clinico-demographic and homocysteine correlates, we conducted a cross-sectional survey of 195 bipolar disorder inpatients. They received questionnaires, clinical measurements and laboratory tests to assess demographic characteristics, anthropometric variables, clinical variables and plasma homocysteine levels. The prevalence of diabetes mellitus (including type 1, type 2 and special types) in Chinese bipolar disorder patients was 14.9%. Analysis of variance or chi-square test showed that compared with non-diabetic bipolar disorder patients, diabetic bipolar disorder patients were older, more often married, had a longer duration of disease, took less olanzapine and had a higher frequency of hypertension. However, there were no significant differences in body mass index (BMI) and homocysteine levels between diabetic and non-diabetic bipolar disorder patients. Logistic regression analysis showed that marital status and duration of disease were independently associated with diabetes mellitus in patients with bipolar disorder after controlling for age, use of olanzapine, presence of hypertension, BMI and homocysteine levels. These findings shed light on the clinico-demographic correlates of the increased prevalence of diabetes mellitus in bipolar disorder patients, rather than the correlation with some metabolic risk factors.