HOT SPRINGS, VA. – An analysis of a large database of bariatric surgery patients has found that those with metabolic syndrome had dramatic improvements in comorbidities but a slightly higher rate of adverse events after 90 days.
Overall, patients with metabolic syndrome tend to be sicker and to have a greater incidence of adverse outcomes and higher mortality than do obese patients who don’t have the syndrome, said Dr. William B. Inabnet III, professor of surgery at Mount Sinai School of Medicine in New York.
Dr. William Inabnet
He and his colleagues at Mount Sinai also determined that the reduction in weight was procedure dependent. "A careful assessment of risk-benefit ratio is warranted to develop the optimal clinical pathway for treating these patients," said Dr. Inabnet at the annual meeting of the Southern Surgical Association.
The researchers examined BOLD (Bariatric Outcomes Longitudinal Database) to identify patients who had undergone bariatric surgery from June 2007 to November 2010 and had metabolic syndrome.
BOLD is maintained by the American Society for Metabolic and Bariatric Surgery Center of Excellence program, and includes 1,157 surgeons at 884 hospitals. The data are self-reported, but some data are verified by on-site inspections. The surgical interventions covered in the registry include gastric banding, Roux-en-Y gastric bypass, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch.
A modified scoring system (0-5) was used to assess comorbidities. For the purposes of the study, metabolic syndrome was defined as a hypertension score greater than 3, a diabetes score greater than 2, a dyslipidemia score greater than 2, and a sleep apnea score greater than 3. (Sleep apnea is not usually included in the definition of metabolic syndrome, but the researchers were interested in the condition as a comorbidity, said Dr. Inabnet.)
Overall, there were 186,567 patients in BOLD, including 23,106 patients who had metabolic syndrome. Those with metabolic syndrome were more likely than other obese patients to be male, older, and white, and to have sleep apnea and an ASA (American Society of Anesthesiologists) classification of 3 or greater. Body mass index was similar for both groups at 47 kg/m2.
Gastric bypass was the most commonly performed procedure, and was the preferred method in patients with metabolic syndrome, followed by gastric banding, sleeve gastrectomy, and duodenal switch. And, said Dr. Inabnet, the researchers "were truly amazed to see that the vast majority of these cases were performed with laparoscopic approaches."
At 30 days, those with metabolic syndrome had increases in mortality, serious complications, readmissions, and reoperations, compared with other obese patients. The increases continued as time went on, and became more pronounced at 90 days post surgery, said Dr. Inabnet.
Overall mortality was very low (0.1%) for the entire cohort of 186,567 patients.
Mortality rates differed by procedure, however. The gastric band patients had the lowest rate (0.1%), followed by 1.2% for duodenal switch, 0.3% for sleeve gastrectomy, and 0.4% for gastric bypass. The serious complications, readmissions, and reoperations at 90 days were also lowest for gastric band patients, followed by duodenal switch, sleeve gastrectomy, and gastric bypass patients.
Metabolic syndrome was associated with the greatest risk for serious complications, according to the authors’ regression model. Those who received the gastric band had a 2.79-fold increase in risk at 90 days, compared with bypass patients, who had a 1.34-fold increased risk.
Follow-up data at 1 year were available for a little more than half of those with metabolic syndrome (12,144 patients). The data show that the decrease in BMI was procedure dependent. The greatest decrease in mean BMI (from 51 to 32) was seen in those who had a biliopancreatic diversion. Mean BMI dropped from 46 to 39 in gastric band patients, from 49 to 36 in those who had a sleeve gastrectomy, and from 48 to 32 in those who had the bypass.
Reduction of comorbidities was also greatest in the duodenal switch group, followed by the bypass, sleeve, and gastric band procedures. For instance, diabetes resolved in 74% of patients who had the duodenal switch, compared with only 28% of those who received the band. There were big reductions in hyperlipidemia and sleep apnea for all the procedures.
The data are limited in that they are self-reported, noted Dr. Inabnet. Even so, the "study confirms the previously held hypothesis that metabolic syndrome confers increased morbidity," said Dr. Bruce Schirmer, vice-chair of the department of surgery at the University of Virginia, Charlottesville. In discussing the paper, Dr. Schirmer noted that BOLD also seemed to show lower overall weight loss and resolution of comorbidities than was previously reported by individual institutions.