Joel Rodriguez, MD, from Duke University in Durham, North Carolina, who presented the study, stated that in a subgroup of women with diabetes, weight loss was similar in the 2 groups of women. "This suggests a counterintuitive association between diabetes and excess weight loss."
Several short-term studies have hinted that being black is associated with resistance to weight loss, both with medical and surgical interventions, Dr. Rodriguez noted, but he added that long-term studies of black women after gastric bypass are lacking.
He and his colleagues conducted a nested, case-control study that involved 78 black women with a mean age of 40 years and a mean preoperative body mass index (BMI) of 51 kg/m². They were matched to 204 white women for age, presurgical BMI, diabetes, obstructive sleep apnea, and hypertension.
Before the surgery, 20.5% of the black women and 21.2% of the white women had type 2 diabetes. Each patient’s percentage of excess weight loss was calculated 1, 2, and 3 years after surgery. "At each time point, the excess weight loss percentage of the [black] women was significantly lower than that of the [white women]," said Dr. Rodriguez.
Three years after surgery, the black women had lost 56.7% of their excess weight; the white women had lost 64.7% (P < .001). However, a subgroup of patients with presurgical diabetes had similar weight loss and similar diabetes remission rates (75% in black women and 77% in white women), he reported.
Senior author Alfonso Torquati, MD, also from Duke University, stated that, "For some reason, diabetes was the great equalizer when it came to weight loss." "Racial differences in excess weight loss only emerged in nondiabetic women," he explained.
In the 60 black women who achieved adequate excess weight loss, 27% had a presurgical diagnosis of diabetes; in the 18 who did not achieve adequate excess weight loss, none had a presurgical diagnosis of diabetes.
Dr. Rodriguez added that, "The preoperative diagnosis of type 2 diabetes remained an independent and significant predictor…of adequate excess weight loss at 3 years, after controlling for confounders."
American Society for Metabolic and Bariatric Surgery (ASMBS) 29th Annual Meeting: Abstract PL112. Presented June 20, 2012.