A new risk calculator may help clinicians better select which patients are candidates for sleeve gastrectomy, researchers reported here.

The new tool, available online, takes into account seven of the most important risk factors and resulted in moderate discrimination (c-statistic 0.682), Philip Schauer, MD, of the Cleveland Clinic, and colleagues reported here at Obesity Week.

Laparoscopic sleeve gastrectomy has risen in popularity in recent years, and some estimates say it is the most common bariatric procedure performed in the U.S., the researchers said.

Estimating the risk of postoperative adverse events can improve surgical decision-making and informed patient consent, they explained.

Even though there are some risk prediction models available, Schauer and colleagues said they have limitations. For instance, the Obesity Surgery — Mortality Risk Score (OS-MRS) was developed based on data from 1995 to 2004, when the procedure was much newer, so it includes only old data, they said.

To create an improved risk prediction tool, they looked at data from the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database, which collects data on more than 150 variables for patients having major surgical procedures in more than 300 centers around the U.S.

Their assessment was based on 5,871 patients who had sleeve gastrectomy in 2012, with a mean age of 43.8, a mean body mass index (BMI) of 45.9, and 80% of them were women.

The 30-day postoperative mortality and composite adverse events were 0.05% and 2.4%, respectively.

For their model, Schauer and colleagues looked at a host of variables and ultimately decided to include seven of the most high-risk ones: history of congestive heart failure, steroid use for chronic conditions, male sex, diabetes, preoperative serum total bilirubin level, BMI, and preoperative hematocrit level.

They found that the model demonstrated a good calibration on the Hosmer-Lemeshow goodness-of-fit test (chi square 16.02, P=0.591) and a moderate discrimination with a c-statistic of 0.682.

They subsequently validated their model on a different validation dataset and found relatively similar performance with a c-statistic of 0.63.

Schauer and colleagues concluded that the data point to the overall safety of sleeve gastrectomy as a treatment for severe obesity and that their new tool could contribute to surgical decision-making, informed patient consent, and prediction of surgical risk — thereby ultimately improving patient care.

They noted that further studies are needed to externally validate the risk model in a different population of sleeve gastrectomy patients.

Mitch Roslin, MD, a bariatric surgeon at Lenox Hill Hospital in New York, who was not involved in the study, noted that the model could be helpful, but cautioned that surgeon interpretation still needs to play a key role in decision-making.

“Yes, if you have heart failure, you are high risk … but that does not mean the surgery shouldn’t be done,” Roslin said. “You may have more to gain.”