Preoperative factors may help predict long-term weight outcomes after gastric bypass, study finds
Out of more than 200 clinical factors, only 3 were associated with greater long-term weight loss: preoperative insulin use, history of smoking, and use of 12 or more medications before surgery.
Certain preoperative clinical factors may help predict patients' weight loss or regain several years after bariatric surgery, a new study suggests.
Using electronic health records from 1 health system, researchers followed 726 patients (mean age, 45.2 years; 83.1% women) for 7 to 12 years after Roux-en-Y gastric bypass surgery, examining the association between baseline patient factors and long-term weight loss or regain. Results were published online Aug. 10 by JAMA Surgery.
After a median 9.3 years postsurgery, patients had a mean (SD) weight loss of 22.5% (13.1%). Out of more than 200 clinical factors (e.g., medications, comorbidities, laboratory test results, demographics), only 3 were associated with greater long-term weight loss: preoperative insulin use (6.8% greater weight loss; P<0.001), history of smoking (2.8% greater weight loss; P=0.009), and use of 12 or more medications before surgery (3.1% greater weight loss; P=0.005).
Factors associated with poorer weight loss were a diagnosis of hyperlipidemia (−2.8% less weight loss; P=0.01), older age (−8.8% less weight loss for every 10 years; P=0.002), and higher BMI (−4.1% less weight loss for every 5 kg/m2; P=0.002). Higher BMI in younger patients and lower BMI in older patients also yielded poorer long-term weight loss.
Despite the study's large cohort and the utilization of long-term weight outcome data, the authors noted that a limitation is the overwhelmingly white study population (97.4%), which prevented the evaluation of race-based differences. The researchers suggested greater interaction with clinicians or unintentional weight loss related to health conditions as potential reasons for the association between greater weight loss and medication use.
The results “suggest that some of the sickest patients have the best outcomes after surgical procedures, a finding that would be new to the literature,” according to an accompanying editorial.
Although the preoperative factors analyzed in the study may guide patient counseling and expectations, future research should focus on behavioral predictors and other potentially modifiable risk factors, the editorialist noted.