Multifaceted intervention helps bipolar disorder patients lose weight

By Joanna Lyford, Senior medwireNews Reporter

An Integrated Risk Reduction Intervention (IRRI) can help overweight and obese patients with bipolar disorder to reduce their body mass index (BMI), US researchers report.

In a randomised controlled trial, patients assigned to the IRRI lost weight significantly faster than their counterparts who received usual care, even if they were regularly taking medications with a known potential for weight gain.

The IRRI was developed by Ellen Frank (University of Pittsburgh, Pennsylvania) and colleagues based on the view that modifiable health risks adversely affect mood and functioning.

It comprised psychiatric treatment and assessment; medical monitoring by a nurse; and a “healthy lifestyle” programme from a lifestyle coach that encompassed bipolar disorder psychoeducation, healthy sleep/wake and social rhythm practices, weight loss and smoking cessation.

To evaluate the intervention, Frank’s team randomly allocated 122 outpatients with bipolar I disorder and a BMI of 25 kg/m² or above to participate in the IRRI or receive usual psychiatric care. The intervention was delivered over a 6-month period and participants were followed up for a further 18 months.

The primary endpoint was change in BMI between baseline and 24 months. Participants in the IRRI group reduced their BMI significantly faster than those who received usual care, with an estimated effect size of –0.51.

The absolute change in BMI by the end of 6 months’ treatment was –2.3%, on average, in the IRRI group versus –0.2%, on average, with usual care. This difference was highly significant.

Frank et al also undertook a moderator analysis to identify and characterise individuals who might be particularly responsive, or nonresponsive, to the IRRI. They found that three variables – higher C-reactive protein, higher total cholesterol and lower instability of total sleep time (TST) – together predicted a faster decrease in BMI with IRRI treatment.

The first two variables are easily obtained in clinical practice, note the authors. The third was measured via actigraphy in the study but could also be elicited through simple inquiry as to how much a patient’s total sleep time varies from night to night.

“Alternatively, clinicians could ask patients to keep a simple sleep diary”, they remark. “Among participants in the present study, instability in TST as recorded in a sleep diary was a highly significant predictor of instability in TST as recorded by actigraphy.”

Writing in Bipolar Disorders, the authors conclude: “[O]ur results do provide a modest level of optimism regarding the possibility of improving the health status of individuals with bipolar disorder.”

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