Depressive symptoms linked to CVD risk in bipolar disorder patients
MedWire News: Depression, but not mania, is significantly associated with an elevated 10-year risk for cardiovascular disease (CVD) in patients with bipolar disorder, research shows.
"Persons with mental disorders are disproportionately burdened by medical comorbidity compared to age-matched controls, notably from CVD," observe Amy Kilbourne (Ann Arbor Veterans Affairs Healthcare System, Michigan, USA) and team.
"Episodic mood episodes unique to bipolar disorder may accelerate the pathophysiology of CVD via an 'allostatic load,' " they add. "However, the evidence is unclear whether depressive or manic symptoms are more salient to CVD outcomes."
To investigate further, the team studied 118 bipolar disorder patients (17% women), aged an average of 53 years, who had at least one CVD risk factor, such as hypertension, diabetes, or hyperlipidemia.
The Internal States Scale (ISS) was used to assess depressive and manic symptoms, with an ISS activation (manic) subscale score of more than 15.5 indicating clinically significant mania symptoms, and a depression subscale score of less than 12.5 indicating clinically significant depressive symptoms.
Data on age, gender, cholesterol levels, blood pressure, current smoking status, and diabetes were used to calculate each patient's Framingham risk score (FRS), with a score of 20% or higher indicating an elevated risk for a serious CVD event within 10 years.
Overall, mean ISS activation and depression subscale scores were 17.2 and 6.9, respectively, with 33% of patients showing clinically significant mania symptoms and 17% clinically significant depressive symptoms. Furthermore, 19% of participants had an FRS of 20% or higher.
After accounting for age, gender, diabetes, and smoking status, the researchers found that participants with significant depressive symptoms were significantly more likely to have an FRS of 20% or higher compared with those without such symptoms, at an adjusted odds ratio of 6.1.
Clinically significant manic symptoms were not associated with an elevated FRS, the researchers note in the Journal of Affective Disorders.
They also found that significant depressive symptoms were associated with elevated body mass index, increased fasting glucose levels, and increased diastolic blood pressure.
Kilbourne and team summarize: "This study found that depressive symptoms, but not manic symptoms, were strongly associated with increased odds of long-term CVD risk among patients with bipolar disorder after adjustment.
"In contrast, manic symptoms had little association with CVD risk factors after controlling for depressive symptoms."
They conclude: "Interventions that address self-management of depressive symptoms may help persons with bipolar disorder decrease CVD risk."
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By Mark Cowen