Metabolic Syndrome Affects Bariatric Outcomes

A patient's gender and ethnicity, as well as the presence of metabolic syndrome, affect the risk of death after bariatric surgery but not the risk of in-hospital complications, according to a retrospective study of more than 30,000 patients.

The findings “suggest that the presence of the metabolic syndrome negatively affects interethnic and gender-specific outcomes after bariatric surgery,” Dr. Javier Esteban Varela said in an interview.

Dr. Varela of the University of Texas at Dallas was the lead investigator of the study and presented the results at the Academic Surgical Congress.

The investigators evaluated in-hospital clinical data on 30,954 patients with and without metabolic syndrome, who underwent bariatric surgery over a 5-year period (2003–2007). The data were obtained from the University HealthSystem Consortium database. The procedures performed included laparoscopic gastric bypass, open gastric bypass, and laparoscopic gastric banding. Most of the patients (85%) were women, 81% were white, 14% were black, and 5% were Hispanic. The researchers defined metabolic syndrome as morbid obesity plus two or more of the following: hypertension, diabetes, and hyperlipidemia.

The main results of the study—which analyzed gender, ethnicity, morbidity, and mortality—were the following:

▸The prevalence of metabolic syndrome among bariatric surgery patients was higher than previously reported by the National Health and Nutrition Examination Survey (NHANES) III study (27% vs. 23%).

▸Overall morbidity after bariatric surgery was significantly higher in patients with metabolic syndrome than in morbidly obese patients without metabolic syndrome (8.6% vs. 5.8%). Mortality was similar between the two groups (0.04% vs. 0.01%).

▸Hispanics with metabolic syndrome had the highest morbidity rates, followed by blacks and whites. Males had higher mortality than females.

▸In-hospital bariatric surgery outcomes were significantly better in patients who had laparoscopic gastric banding than in those who had gastric bypass. Laparoscopic gastric banding was associated with fewer complications (3% vs. 10%), shorter length of stay (1 vs. 3 days), and lower in-hospital costs ($9,000 vs. $13,000) than was gastric bypass.

The higher complication rates in patients with metabolic syndrome indicate that these patients might benefit from less-invasive procedures, such as laparoscopic gastric banding, said Dr. Varela, who also is director of minimally invasive surgery for the VA North Texas Health Care System. He added, however, that this hypothesis needs to be tested further before any clinical recommendations can be made. Long-term studies evaluating the efficacy of these bariatric procedures in resolving metabolic syndrome in morbidly obese patients are warranted, he said.

The finding that metabolic syndrome was higher among the Hispanic population had been observed previously, he noted.

Asked to comment on the results, Dr. Myriam Curet, a bariatric surgeon and professor of surgery at Stanford (Calif.) University, said that common obesity-related comorbidities—components of what is now called metabolic syndrome—have previously been recognized as risk factors for increased complications after any type of surgery, including bariatric surgery. But the findings of this study are helpful because they demonstrate the association using a large clinical database, and are therefore more translatable to a broad range of practices than are the results of studies from single institutions with a few hundred patients.

She also found the ethnic differences noteworthy. It has been recognized that after bariatric surgery, men do worse than women, and black women tend to do worse than white women, so the data on the ethnic differences are “pretty powerful,” she said.

These results reveal other issues that need to be investigated, Dr. Curet said in an interview. For example, it is important to determine whether something can be done before surgery to reduce risk and to properly counsel patients with the risk factors identified in the study.

“Defining who are the appropriate candidates [and] who are high-risk candidates, and deciding what we can do for those high-risk candidates to make them lower-risk candidates are clearly important issues,” Dr. Curet said. She cautioned against assuming that less-invasive procedures are more appropriate for higher-risk patients, however, pointing out that although some complications with laparoscopic banding are less severe than with gastric bypass procedures, other complications and the need for reoperation are the same as or higher than they are with laparoscopic banding.

In-hospital outcomes were better and costs were lower with gastric banding, Dr. Javier Esteban Varela said. University of Texas Southwestern Medical Center