Elevated risk for lipid disorders seen in bipolar.

HOLLY WOOD, FLA. -- Bipolar disorder is an independent risk factor for lipid disorders among patients without other known risk factors, according to a large, retrospective, managed care claims database study.

When a patient also had thyroid disorder or diabetes mellitus, for example, the association was no longer significant.

Dr. Quinton E. Moss and his associates also found the association between bipolar disorder and elevated risk remained after they controlled for current use of antipsychotic and lipid-lowering medications. This finding was important because treatments for bipolar disorder, particularly some atypical antipsychotics, can increase lipid abnormalities, he said in an interview at his poster at a meeting of the New Clinical Drug Evaluation Unit sponsored by the National Institute of Mental Health.

The risk for lipid disorders was greatest among bipolar patients in their 20s and 30s. This means the increased risk for dyslipidemia, hypercholesterolemia, or hypertriglyceridemia was independent of lipid changes typically associated with aging, said Dr. Moss, CNS assistant medical director, medical and scientific affairs, at i3 Research in Basking Ridge, N.J.

It is widely accepted that there is a greater risk of metabolic syndrome and cardiovascular disease among people with bipolar disorder, Dr. Moss said (Ann. Clin. Psychiatry 2008;20:131-7). "What we are trying to do is look at the effect of various comorbidities such as thyroid disorders and diabetes mellitus. Do these disorders increase the risk?"

Dr. Moss and his colleagues compared 33,019 enrollees of a U.S. health insurer who had bipolar disorder and a diagnosis of a lipid disorder, thyroid disorder, or diabetes with an additional 1 million controls with no Axis I mood or psychosis diagnoses.

Patients were aged 20-55 years (mean age, 39 years in both groups). Men comprised 35% of the bipolar disorder cohort and 52% of controls.

Patients with bipolar disorder and no comorbid thyroid disease or diabetes had a significantly increased likelihood of having lipid disorders (odds ratios ranged from 1.85 to 3.07, depending on patient age and sex). In contrast, the bipolar disorder and lipid disorder association was no longer significant if either of the comorbidities was present (OR ranged from 0.51 to 1.27).

Because some medication use can alter lipid levels (Neuropsychobiology. 2006;53:108-12), Dr. Moss and his associates performed a subanalysis that excluded 31% of the bipolar sample taking an antipsychotic agent and the 13% taking a lipid-lowering drug.

"Looking at those who have not been treated with an atypical antipsychotic or those who have not received a lipid-lowering agent--we still saw a relationship." Bipolar patients not taking these medications but who had concomitant thyroid disorder or diabetes were not significantly more likely to have a lipid disorder, with the exception of men aged 30-34 years or 40-55 years and women aged 45-55 years.

"Folks who have bipolar disorder are being screened for lipid disorders before [being prescribed] an atypical antipsychotic, supposedly," Dr. Moss said. "But there is a group with bipolar disorder not about to be treated who have an increased risk."

Regardless of sex, the odds ratio was higher if patients were aged 20-24 years, 25-29 years, 30-34 years, and 35-39 years versus the older age groups. Again, this applied only to patients without one of the comorbidities.

There was no significant increased risk by age if one of the comorbidities was present, except among men aged 30-34 years and 50-55 years.