Does Weight Loss Reduce Deaths? Look Again

Henry R. Black, MD


September 23, 2013

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Hi. I'm Dr. Henry Black, Clinical Professor of Internal Medicine at the New York University School of Medicine, a member of the Center for the Prevention of Cardiovascular Disease, and former President of the American Society of Hypertension.

Today I want to talk about the so-called Look AHEAD study.[1] This was a very large undertaking by the National Institutes of Health and was run by Rena Wing at Brown University, along with many collaborators. The idea was to see if intense dietary instruction would reduce cardiovascular events over the long haul. It is well known that if you stay on a diet and lose some body weight (at least 7%, or more in some cases), then cardiovascular risk factors will improve. But there has never been a study that looked at outcomes. And we do lots of things that are based on outcomes. That's how we test drugs and devices. We should apply lifestyle modification, such as what was done in Look AHEAD, to cardiovascular events as well.

This was a large undertaking with more than 5000 patients in each group. The intensive group got weekly counseling for the first several years and then less frequently after that. The control group received counseling about 1-2 times a year and then rarely after that.

The study was stopped for futility. It is an unusual reason for stopping a study. The way that the Data and Safety Monitoring Board saw it was that there was no way that the hypothesis could be shown, the hypothesis being that you would lower cardiovascular events with this intensive dietary and exercise therapy. At the end of 9.5 years they stopped the study, although it was planned to continue for 13.5 years.

They found no reduction in cardiovascular events -- none at all, even in individual events. There seemed to be no statistically significant benefit. The cardiovascular risk factors were better, anxiety and depression were better, sleep apnea was reduced, and blood pressure was reduced by a small amount, but the overall important event was not reduced at all. The investigators talked about the benefit to cost because fewer drugs were used, fewer visits were made to the hospital, and other things related to cost. What they never told us was how much it cost to do all of those interventions. Where are we going to get people who could be trained to do that, and where are we going to get citizens to come in once a week for their sessions? They left those out completely.

I think that right now, it is certainly appropriate to recommend dietary weight loss. They achieved about 8% body weight reduction in the intensive group in the first year compared with 0.7% in the control group. But at the end of the 9.5 years, it was 6% vs 3.5%, so it was not that impressive.

Right now we have to look ahead and use this intervention for what it's good for, which is to improve risk factors, and not anticipate that it is ever going to reduce events alone. We are going to need drugs for most people, and that, to me, is the bottom line. Thank you very much.


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