Skip to main content

-- A Geisinger Health System study of patients who underwent gastric bypass surgery found that those who used insulin prior to surgery, had a history of smoking, or took 12 or more medications maintained the greatest weight loss 7 to 12 years after the surgery. The study was published online Wednesday by JAMA Surgery.

Michelle R. Lent (right), Ph.D., a Geisinger Obesity Institute researcher, and her team examined the electronic health records of 726 patients for preoperative conditions and factors – including medications, chronic diseases, lab results and demographics – and determined percentage weight loss following the surgery. Patients in the study averaged a 22.5 percent weight loss 7 to 12 years after surgery.

“While bariatric surgery is the most effective long term treatment for obesity, some patients do better than others when it comes to weight loss,” Dr. Lent explained. “If we can identify those patients who may be at risk for losing less weight, we can tailor their treatment to help them lose as much weight as possible.”

The study is the first to find that patients with diabetes and using insulin demonstrated the greatest long-term weight loss after gastric bypass surgery. Those patients lost seven percent more weight than the average.

“Patients using insulin ended up being the slow, steady weight loss winners, which we did not expect,” Lent said. “We theorize that may be because these patients are typically advised to watch their diets closely to manage their diabetes. Perhaps the dietary recommendations associated with insulin use help them lose more weight when compared with other patients.”

Patients with a history of smoking or those who took 12 or more medications lost 3 percent more weight.

Smoking was a surprise since it is generally associated with worsening health outcomes. But Lent says because those patients had to quit smoking in order to have the surgery, they may have already demonstrated a history of changing their behavior to improve upon their health and are therefore also able to change their eating behaviors.

Those on the most medications also may have had the most to gain from the weight loss surgery.

“They could possibly be sicker, so they may be the most motivated to change their behavior,” Lent said. “Or, those who are taking that many medications may already have more touch points within the health system, so they may be seeing doctors more frequently.”

Older patients (55 and older) lost nearly 9 percent less weight than the average. Patients with higher body mass indexes (BMI) also lost 4 percent less weight, while those with preoperative high cholesterol lost 3 percent less.


About Geisinger
One of the nation’s most innovative health services organizations, Geisinger serves more than 1.5 million patients in Pennsylvania and New Jersey. The system includes 13 hospital campuses, a nearly 600,000-member health plan, two research centers and the Geisinger Commonwealth School of Medicine. A physician-led organization, with approximately 32,000 employees and more than 1,800 employed physicians, Geisinger leverages an estimated $12.7 billion positive annual impact on the Pennsylvania and New Jersey economies. Repeatedly recognized nationally for integration, quality and service, Geisinger has a long-standing commitment to patient care, medical education, research and community service. For more information, visit, or connect with us on Facebook, Instagram, LinkedIn and Twitter.