August 11, 2016
2 min read

Preoperative clinical factors affect long-term weight loss after RYGB

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Preoperative insulin use, history of smoking and use of 12 or more medications are associated with greater long-term postoperative percentage weight loss after Roux-en-Y gastric bypass, according to findings published in JAMA Surgery.

Michelle R. Lent, PhD, of the Geisinger Obesity Institute at the Geisinger Clinic in Danville, Pennsylvania, and colleagues evaluated data on 726 adults (mean age at time of surgery, 45.2 years; mean BMI, 47.5 kg/m2; 83.1% women) who underwent bariatric surgery before October 2007 to determine the association between preoperative clinical factors and long-term weight loss after Roux-en-Y gastric bypass (RYGB). Participants were followed for 7 to 12 years after surgery.

Electronic medical records were assessed for preoperative clinical factors, and percentage weight loss was determined.

Overall, mean percentage weight loss was 22.5%, and mean percentage excess weight loss was 50.2%.

Greater long-term postoperative percentage weight loss was associated with preoperative insulin use (6.8%; P < .001), history of smoking (2.8%; P = .009) and use of 12 or more medications (3.1%; P = .005). Poorer long-term postoperative percentage weight loss was associated with preoperative hyperlipidemia (–2.8%; P = .01), older age (per 10-year increase, –8.8%; P = .002) and higher BMI (per 5-point increase, –4.1%; P = .002).

The use of diabetes therapies decreased from 46.1% before surgery to 18.2% at follow-up (P < .001). The use of therapies for hypertension and dyslipidemia also decreased (P < .001 for both).

“Overall, few preoperative clinical factors were associated with weight change in the long-term postoperative course,” the researchers wrote. “Future studies are needed to replicate these findings, particularly surrounding insulin use. Comprehensive investigations of potential preoperative psychosocial and behavioral factors or other modifiable preoperative or early postoperative factors that may influence weight in the long term could also help to identify patients at risk for suboptimal outcomes. These results can help to guide clinical care and improve patient-directed informed consent discussions about bariatric surgery.”

In an accompanying editorial, Amy Neville, MD, MSc, FRCSC, of the Bariatric Centre of Excellence, The Ottawa Hospital in Canada, wrote that the study findings “challenge our current understanding and the current literature regarding risk factors for weight gain.”

“As a novel (and contradictory) finding, this must be interpreted with caution until additional studies can further investigate,” she wrote. “This study and the preoperative factors it analyzed are of academic interest and may guide patient counseling and expectations, but future work must focus on behavioral predictors and other potentially modifiable risk factors if we are to best serve our patients.” – by Amber Cox

Disclosure: The researchers report no relevant financial disclosures.