Melton GB et al. (2008) Suboptimal weight loss after gastric bypass surgery: correlation of demographics, comorbidities, and insurance status with outcomes. J Gastrointest Surg 12: 250–255

The majority of severely obese individuals who undergo Roux-en-Y gastric bypass (RYGB) surgery achieve their target weight loss; however, some do not and the reasons for these failures have not been comprehensively studied. Melton et al., therefore, conducted a retrospective, single-center study in the US to identify factors (including demographics, comorbidities and insurance status) associated with poor weight loss after RYGB.

Data for 495 morbidly obese patients (mean age 42 years) who underwent RYGB performed by a single surgeon between 1999 and 2004 were analyzed. Preoperatively, patients' mean excess body weight was 92 kg. Obesity-related comorbidities were common, and 30% of the cohort had diabetes. Suboptimal weight loss (SWL) was defined as failure to lose ≥40% excess body weight by 12 months after RYGB.

At 12 months, participants had on average lost 60% of their excess weight, but SWL had occurred in 55 patients (11%). On adjusted multivariate analysis, increased BMI, male sex and diabetes were associated with SWL, but insurance type was not. In the whole cohort, diabetes resolved by 1 year after RYGB in 78% of affected individuals, and similar rates of diabetes resolution were observed in patients with successful weight loss and with SWL, respectively. By contrast, hypertension resolved in significantly more patients with successful weight-loss than with SWL.

These findings could aid patient selection for increased perioperative dietary supervision and counseling and, possibly, for surgical procedures that result in a greater degree of malabsorption.