(Reuters Health) - Obese patients who need to have their gallbladder removed and also need weight-loss surgery may have fewer complications if they get the gallbladder procedure first, a Swedish study suggests.

For the study, researchers examined data on about 79,000 patients who had surgery to remove the gallbladder, a procedure known as a cholecystectomy, and almost 36,000 people who had a type of weight-loss surgery known as a Roux-en-Y gastric bypass. Most of these patients only had one of the procedures, but about 2,650 had both surgeries either simultaneously or separately.

Among patients who had both surgeries, people who had the weight-loss operations first were 35 percent more likely to have complications than individuals who had the gallbladder surgery first, the study found.

Having both operations at the same time was twice as likely to lead to complications as having the gallbladder procedure done first.

“For patients with symptomatic gallstones and obesity (i.e., considering both cholecystectomy and gastric bypass), cholecystectomy should preferentially be performed before gastric bypass,” said lead study author Dr. Viktor Wanjura, a surgeon at Orebro University Hospital in Sweden.

But gallstones that don’t produce symptoms “should never be treated surgically,” Wanjura said by email. “Doing so would introduce unnecessary complications in many patients that would never be troubled by their gallstones at all during their lifetime.”

The study wasn’t a controlled experiment designed to prove whether or how doing one of the two procedures before the other one might influence complication rates.

It’s possible that patients might have nutritional deficits after weight-loss surgeries that might contribute to a higher complication rate with the gallstone removal procedures, Wanjura said. But more research is needed to clearly understand the cause of complications.

Gastric bypass, one of the more common types of weight-loss surgeries, reduces the stomach to about the size of an egg and rearranges the intestine so that food bypasses part of it.

When researchers looked at all of the patients in the study, including the majority of people who only had gallbladder or weight-loss procedures but not both, they found 2.3 percent of people had complications with gallbladder operations and 2.7 percent had complications with weight-loss surgery.

Among people who had both procedures, roughly 13 percent had complications regardless of which operation came first or second.

When gallbladder operations were done after weight-loss surgery, however, almost 16 percent of patients had complications, compared with 8 percent of patients when the gallbladder operation was done first.

Even though the study doesn’t explain why complication rates differed, the results suggest that it makes sense for patients to discuss the ideal order of both operations with doctors before they have surgery, said Dr. Anita Courcoulas, chief of minimally invasive bariatric and general surgery at the University of Pittsburgh Medical Center

“I think patients need to be aware that although gallbladder surgery is one of the most common abdominal operations performed, that complications are possible especially in people who also have the diseases of obesity, diabetes, and others,” Courcoulas, who wasn’t involved in the study, said by email.

“A patient and their surgeon should have an open and shared decision-making conversation to together weigh the risks and benefits of the timing of both gallbladder and bariatric surgery,” Courcoulas added. “These decisions are best individualized, taking into account the patient’s symptoms, anatomy, and other risks for surgery.”

SOURCE: bit.ly/2zKfn98 British Journal of Surgery, online October 18, 2017.