Editor's Note: Clinical trials in the early 2000s showed that lifestyle modification programs geared for weight loss can delay or prevent the onset of type 2 diabetes. Since then, many community programs have tried to replicate those results, targeting a large population: As many as 82 million Americans are thought to have prediabetes. The potential benefit of educating high-risk individuals is huge, it would seem -- but so, too, is the cost.
It's unfair to burden society with the expense of real-world programs because their efficacy is unclear, writes Richard Kahn, PhD, of the University of North Carolina at Chapel Hill, in a recent issue of Diabetes Care. Medscape spoke with him about the benefits, costs, and uncertainties associated with these programs.
Medscape: You recently described the exercise and diet regimens used in major diabetes prevention trials as neither simple nor straightforward. Can you explain what you meant by that?
Dr. Kahn: These people had an enormous amount of attention given by health professionals. They were called, emailed, and seen in person. They were cajoled. They were encouraged. They were given free health club memberships. They were given free food, diet supplements. They were given free exercise equipment. They were given anything they could possibly use to adhere to the regimen -- which would, of course, never occur in real life.
Medscape: Studies show that weight loss is the single biggest factor in diabetes prevention, but, as you write, weight regain is almost certain, even in a highly motivated group. If regain is inevitable, is the initial weight loss even worthwhile?
Dr. Kahn: That's a good question. From a psychological standpoint, my guess -- and it would be a guess -- is that people feel good about the initial weight loss. They subsequently may feel depressed that they regained it. I think it's hard to know whether that initial weight loss was beneficial and that regaining it now made you in worse shape, psychologically.
From a medical point of view, it doesn't look like that initial weight loss does much, if anything. For some clinical effect, you have to lose substantially more weight -- 20%, 25% of your body weight, as in bariatric surgery, as opposed to 2% to 4%. So you need much more for some clinical effect. Now, where between 2% and 25% will it work? We don't know because there has never been any kind of study to see which is most effective.
Medscape: A meta-analysis published in the same issue of Diabetes Care concludes that, although difficult and expensive, these programs are effective. How do you reconcile the difference in these authors' conclusions from yours?
Dr. Kahn: If you look at that article carefully, the first thing you see is the overwhelming number of studies that didn't even go out to 1 year. Only a handful do, and at 1 year people are regaining their weight in every one of the studies except for maybe one in which the weight seems to be coming back but very slowly. So if you just take early results, you think everything is great -- but that's not the case.
The second thing is that those interventions -- almost every one -- were expensive. Number three is the assumption the authors make that that amount of weight can be lost forever. That has simply never been seen except in bariatric surgery. Look at that paper carefully: There are some fundamental assumptions and tenets that are unproven or don't exist.
Medscape: You point out that weight would have to come off and stay off for about 30 years for the programs to become cost-effective, and that the intervention would have to cost less than $200 per year and result in weight loss of 4%. Correct me if I'm wrong, but it sounds like you're saying in the article that this isn't feasible.
Dr. Kahn: No, you're not wrong. Let's back up a little bit. First, you'd have to see appreciable weight loss. It would have to stay off for a long time. In fact, all of the cost-effectiveness analyses made the assumption that the weight will be lost and held off for life, which, it turns out, is unrealistic. Or maybe it's realistic but not in today's world.
The second thing is that every cost-effectiveness study assumes that the cost of the program to keep it off -- the lifestyle modification program -- is minimal. That has not been found to be true so far in any real-life studies.
Medscape: How can we reduce the cost of interventions without sacrificing efficacy?
Dr. Kahn: We don't know what we can do. First of all, there's no evidence that we can achieve substantial weight loss for a minimal amount of money. That said, we're talking about [weight loss] for a population -- it's important to point out -- not for an individual. Some people decide, "I'm going to do it," and they do it. They've invested nothing. That's great for them, but we're not arguing about whether people should be encouraged to lose weight. What we're arguing against is having society pay the bill for this when it hasn't been effective.
Medscape: What's the main takeaway for clinicians, then?
Dr. Kahn: People who are overweight or obese should be strongly encouraged by their healthcare provider to lose weight and keep it off. If a provider feels that there is a good resource in the community, he or she should refer the person to that resource. But I don't think it's fair at this point, given how difficult it is to keep weight off, that society pay for the intervention. The individual should pick up that cost.
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Cite this: Diabetes Prevention Programs: A Waste of Money? - Medscape - Jun 19, 2014.