A simple, three-step tool could reduce surgical complications by more accurately predicting the best type 2 diabetes candidates for bariatric surgery, a London-based research team reported this week.

Weight loss surgery is only successful in about one in five candidates, study author Rachel L. Batterham, PhD, and U.K. colleagues wrote in Diabetic Medicine, and it’s often difficult to weigh the benefits of a surgical path against the possible risks. Batterham and her team also found that, post-surgery, keeping weight off had more of an impact on a patient’s overall well-being than which surgery they chose.

Bariatric surgery, which is offered in the form of either a Roux-en-y gastric bypass or sleeve gastrectomy, is a recognized treatment option for type 2 diabetes patients with a body mass index of 35 or higher, the researchers wrote. Still, though the surgery alters hormones that control blood glucose, reduces long-term complications of type 2 diabetes like eye and kidney damage and offers patients the option of discontinuing their diabetes medication after hospitalization, the procedure isn’t foolproof.

“Bariatric surgery can be highly beneficial, yet the results are highly variable, so we set out to devise a better way of identifying which people with [type 2 diabetes] will benefit most,” Batterham said in a release from University College London, where she’s based.

Batterham and colleagues’ three-part formula takes into account the medications a patient is taking, their HbA1c level—a blood glucose monitor—and how long ago they were diagnosed with diabetes mellitus, Batterham and co-authors wrote. These factors calculate an individual’s “DiaBetter” score, which is an alternative to today’s commonly used DiaRem score.

Previous research has shown patients with a low DiaRem score are more likely to see type 2 diabetes remission than those with high scores, according to the study. With the DiaBetter calculation, remission rates in the lowest quintile of DiaBetter scores were 98 percent, compared to the highest quintile’s 19 percent.

There didn’t appear to be any difference, after adjustment for weight loss, between the two bariatric surgery options, Batterham et al. said in their paper. Percentage of weight loss two years after surgery was, however, a strong predictor of the likelihood of remission. For every 5 percent weight loss, the authors wrote, the odds of diabetes remission increased by 54 percent.

Still, despite its benefits, bariatric surgery can be complex, limited-access and expensive.

“Over 2 million people in the U.K. are eligible for assessment for bariatric surgery, and yet only 6,000 undergo the procedure each year,” Batterham said in the release. “Given the limited access to surgery, it’s vital that we ensure it’s offered to those who will benefit the most, and that they’re well-supported long after the surgery.”