Finding Balance

Balancing the Safety and Effectiveness of Bariatric Surgeries

Getting a handle on the real world effectiveness of any medical treatment is devilishly hard. For surgery, it’s even harder. Randomized controlled trials are not impossible, but almost. And many variables come into play that can cause big swings in effectiveness. That list starts with surgical skill and the quality of a program. And it goes on from there. But yesterday in Annals of Internal Medicine, a new study gave us important insights for understanding the balance of safety and effectiveness of different bariatric surgeries.

The Largest Study of Long-Term Outcomes Yet

This study analyzed the outcomes for more than 65,000 patients for up to five years. Qualitatively, the numbers are not a big surprise. But the big news is that we have a good fix how to compare the real-world effectiveness of different bariatric procedures. Gastric bypass provides the most weight loss – on average. After five years, patients lost an average of 26 percent of their starting weight. Compare that to 19 percent for gastric sleeve patients.

Weighing Benefits and Risks

However, that extra effectiveness comes at a cost. The study also looked at major adverse events in the first 30 days. Among sleeve patients, 2.6 percent had a major complication in the first 30 days. For gastric bypass patients, the number was significantly higher – 5.0 percent.

This difference at least partially explains why more patients opt for a sleeve than a bypass. Bariatric surgery is a bit scary for many people. They tend to overestimate the risks. They hear from friends and family, “You should be able to do this on your own.” It’s a lie repeated so often that people believe it.

So it’s not surprising that many people opt for the safest procedure when they come to the realization that bariatric surgery will benefit them. Today, more than three times as many people opt for a sleeve as for a bypass.

Ten years ago, gastric bands were the thing. They seemed safer in the short term. And they were seen as “reversible.” Less daunting. But in the long term, it turned out that many people who had bands required follow-up surgeries – usually to remove the band. So bands have all but disappeared from common use.


As good as these data are, they’re not perfect. The study doesn’t tell us about outcomes on important complications of obesity, like diabetes. And complication rates beyond 30 days are unavailable. Also, we have the issue of missing data. Fortunately, at five years, the follow-up for sleeve patients was 86 percent. But for some subgroups, it was as low as 55 percent.

So this is an important milestone, but it’s also only a start. The PCORnet initiative that produced this research promises to yield even more important information down the road. And in the end, patients and providers will have better information for making important decisions about obesity care.

Click here for the study and here for a companion editorial. For further perspective, click here and here.

Finding Balance, photograph © Ian@NZFlickr / flickr

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October 31, 2018