Here is an update on weight loss after gastric bypass surgery that has surgeons scratching their heads because of an unusual finding in a certain population of patients years after their surgery.
The gastric bypass surgical procedure (also referred to as “Roux-en-Y” gastric bypass surgery) for weight loss consists of two parts: The first part is where the stomach is altered to create a small stomach pouch that can hold only about one cup of food. The second part is where the connection from the small stomach pouch bypasses the first part of the duodenum and goes further down the digestive tract directly to the jejunum. The result is that the patient can only eat small portions at a time with less calories being absorbed by the small intestine.
The popularity of this procedure is that it gets the job done―especially with severely obese patients because it on average causes patients to lose up to 60% of their pre-surgery weight. However, not everyone maintains their significant weight loss after a few to several years afterward.
According to a press release issued by the American Association for the Advancement of Science, researchers are attempting to pinpoint whether there may be some before-surgery patient factors that can be used as predictors of why one bariatric surgery patient may do better than another patient. The goal of knowing this is to help all weight loss surgery patients maintain their weight loss.
To address the question of whether there are any potential predictors, researchers examined the medical records of 726 “Roux-en-Y” surgery patients over a period that ranged from just before surgery to 7 to 12 years after surgery. What they noted besides how much weight was lost―percentage weight loss (%WL)―were some preoperative clinical factors that included medications the patients had been on, comorbidities, laboratory test results, demographics, and others.
What the data surprisingly revealed was an indication that the sickest patients tended to maintain their weight loss better than those who were relatively healthier. The press release notes that the researchers found that preoperative insulin use, a history of smoking, and use of 12 or more medications before surgery were associated with greater long-term postoperative percentage weight loss. Those who had high cholesterol, were older and had a higher BMI were less successful at maintaining their weight loss from surgery.
According to a commentary about the published data, Amy Neville, M.D., M.Sc., F.R.C.S.C., of the Ottawa Hospital, Ottawa, Canada wrote that, “The results of this study appear to suggest that some of the sickest patients have the best outcomes after surgical procedures, a finding that would be new to the literature.”
However, she also points out that there is a need for more studies to examine what is actually happening and hints that the association with insulin-use in the patients who better-maintained their weight loss may hold the answer. The researchers who performed the study speculate that participants who took the most medications before surgery had better weight loss outcomes due to their greater interaction with health care professionals for their treatment.
Regarding predictors of patient weight loss maintenance, is that for now there appears to be few if any. The authors of the study concluded that preoperative insulin use was strongly associated with better long-term %WL, while preoperative hyperlipidemia, higher body mass index, and older age were associated with poorer %WL.