ORLANDO – Although obesity is more prevalent among blacks, fewer get bariatric surgery, and for those who do, the outcomes are less efficacious than for whites and Hispanics, according to analysis of a national database, examining the influence of ethnicity on bariatric surgery.
"All qualified obese patients, particularly the rapidly growing black population, need improved access to bariatric surgery to reduce mortality," said Dr. Ranjan Sudan, vice chair of education in the department of surgery at Duke University, Durham, N.C. He presented his unpublished abstract at the annual Digestive Disease Week.
Dr. Ranjan Sudan
Studies have shown that bariatric surgery is an effective treatment for obesity and decreases mortality, but the reason behind the disparity and surgery outcomes is rather nuanced and not so clear (N. Engl. J. Med. 2007;357:753-61).
A 2012 study at the Louisiana State University System, Baton Rouge, found that white females appeared to lose more weight than did black females regardless of the type of bariatric surgery, although both races experienced surgical complications. Also, "black patients may be less likely to undergo bariatric surgery without insurance coverage," the authors wrote (Adv. Ther. 2012;29:970-8).
Meanwhile, a 2012 meta-analysis looking at ethnic differences in weight loss and diabetes remission after bariatric surgery found that for the percentage of excess weight loss, bariatric surgery was more effective in whites than in blacks, regardless of procedure type. "Further studies are needed to investigate the exact mechanisms behind these disparities and to determine whether ethnic differences exist in the remission of comorbidities after bariatric surgery," the authors wrote (Diabetes Care 2012;35:1951-8).
"It could be because of underlying difference in physiology among races," an area that is still poorly-understood, Dr. Vic Velanovich, professor of medicine at the University of South Florida, Tampa, said in an interview. Also, "Is this a problem of geographic variation?" he said, commenting on Dr. Sudan’s findings. "Are blacks getting their health care in such a way that they don’t have access to bariatric surgery? And the third issue is cultural. It could be very well that [the] cultural view of body image is different. So there are a lot of unanswered questions," said Dr. Velanovich, who was not involved in the study.
Dr. Sudan and his colleagues examined the primary Roux-en-Y gastric bypass surgery (RYGB) data from the American Society for Bariatric and Metabolic Surgery database, submitted by more than 1,000 surgeons and 700 hospitals between June 2007 and September 2011.
All patients gave research consent and were eligible for 1-year follow-up.
Of the 135,000 patients, 79% were white, 12% black, and 9% Hispanic. Compared with whites at baseline, black patients were younger (43 years vs. 46 years), heavier (body mass index of 50 kg/m2 vs. 48 kg/m2), and were more often hypertensive (58% vs. 53%).
Among black patients who were undergoing RYGB, 15% were male, compared with 23% white and 22% Hispanic males. More black patients had a history of hypertension (57%), compared with whites (52%) and Hispanics (41%). Hispanic patients had the least comorbid disease burden, said Dr. Sudan.
Meanwhile, more white patients had diabetes (32%), compared with Hispanics (31%) and blacks (30%), at baseline.
Follow up rates were 60% in white patients, 50% in Hispanics, and 49% in blacks.
Overall, the benefits of RYGB were significant in the three groups at 1-year follow-up, but the procedure was less efficient for black patients, according to the analysis.
For instance, although fewer black patients had diabetes at baseline, at 1-year follow-up a higher percentage of them had diabetes with less decline in diabetes rates (from 30% to 13%, decline of 59%), compared with whites (from 32% to 11%; –65%), and Hispanics (from 31% to 12%; –61%.)
Black patients also had less decline in the mean body mass index (–30%), compared with whites (–34%), and Hispanics (–32%). Their hypertension also declined less (–35%) than in whites (–49%), and Hispanics (–50%).
The mortality rates within 30 days were similar for all three group (0.23%-0.26%), but black patients had a higher rate of total adverse events (22%), compared with whites and Hispanics (17% each).
The study has some limitations, said Dr. Sudan. Some of the data is self-reported, and researchers did not stratify disease severity by ethnicity.
Recent studies shows that grade 2 or higher obesity (BMI of 35 or more) is most prevalent among blacks (26%), compared with whites (15%) and Hispanics (15%). The overall rate for all ethnicities is 15.5%. (JAMA 2012;307:491-7). Black women also have the highest rate of grade 2 or higher obesity (31%), followed by black men (21%), Hispanic women (18%), white women (17%), white men (12%), and Hispanic men (11.4%).