Patients with bipolar disorder have a higher prevalence of hypertension than in the general population, putting them at risk for subsequent heart disease, researchers said here.

In a single-center study, the prevalence of hypertension among patients with bipolar disorder was 45%, compared with 30.5% in the general population, Dale D’Mello, MD, of Michigan State University, and colleagues reported at the American Psychiatric Association meeting here.

“Our study suggests the possibility of a link [between bipolar and hypertension],” D’Mello said during a scientific session here.

Previous research has shown that patients with bipolar disorder have a disproportionate burden of cardiometabolic disorders, including heart disease, metabolic syndrome, and stroke.

Yet the underlying mechanisms of this association aren’t well understood.

So the researchers assessed 99 patients with bipolar disorder who were treated at St. Lawrence Hospital in Lansing, Mich., between 2002 and 2006.

About half of the patients were male, they had a mean blood pressure of 137/83 mm Hg, and their mean body mass index (BMI) was 30.

There was a high prevalence of smoking, D’Mello said, and 37% were obese.

The researchers found that 45% of the patients were hypertensive—a proportion much higher than recent data from a Healthy People 2010 analysis, which put the prevalence of hypertension in general population at 30.5%.

D’Mello said the hypertensive patients were older (mean age 44 versus 37) and more obese (mean BMI 33 versus 28).

They also had higher mean scores on a mania scale (40 versus 35, P=0.04), as well as earlier onset of bipolar disorder, with a mean age of 24, compared with 29 in nonhypertensive patients (P=0.05).

“They start having hypertension at an earlier age, and have a longer duration,” D’Mello said.

But he also noted, “there were many confounding factors we didn’t control for in this study.”

For example, certain antipsychotic drugs—which some patients may have taken earlier in their lifetimes—can lead to metabolic syndrome. The possible role of these medications should be examined in the future, he said.

If it’s found that bipolar disease is indeed a cause of hypertension, then “treating bipolar disease may prevent morbidity and mortality,” he added, comparing the link to studies that have pointed to depression as a risk factor for coronary artery disease.

“As psychiatrists,” he concluded, “we have the opportunity to manage and perhaps prevent a physical disorder.”

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Primary source: American Psychiatric Association

Source reference:
D’Mello D, et al “The prevalence and clinical consequences of concurrent hypertension in patients with bipolar disorder” APA 2010; Abstract NR4-17.