The risk of death for 1 year after bariatric surgery is significantly higher in patients who are “superobese” and those with a greater burden of preoperative comorbidity than in other patients undergoing the procedure, according to results of a retrospective study.
The findings suggest that bariatric surgery must be considered carefully in patients with body mass indexes of 50 kg/m
To define postsurgical mortality risk and identify associated factors, the researchers performed a retrospective study of 856 patients who underwent bariatric surgery at 12 Veterans Affairs medical centers between 2000 and 2007. The number of these procedures performed at VA centers per year rose more than threefold during this interval Arch. Surg. 2009;144:914–20).
The study population had a mean age of 54 years and was predominantly male (73%) and white (84%). Three-fourths of the procedures were open surgeries; the rest were laparoscopic. About a third (36%) of the patients were considered superobese, with BMIs of 50 or greater.
A total of 54 patients (6.5%) died during a median follow-up of 984 days. Overall, 30-day mortality was 1.3%, 90-day mortality was 2.1%, and 1-year mortality was 3.4%.
Superobese patients had a significantly higher rate of death, particularly at 90 days (3.6%) and at 1 year (5.2%), than did patients with lower BMIs. “Exclusion of superobese patients from our cohort would have reduced the overall 30-day, 90-day, and 1-year mortality rates by approximately one-third,” Dr. Arterburn and his colleagues wrote.
Possible explanations for this result include the greater technical difficulty of the surgery in superobese patients because of added visceral adiposity and hepatomegaly, which in turn increases intra-abdominal pressure and reduces visualization.
Superobese patients also appear to be at greater risk for wound complications such as infections or dehiscence, compared with less obese patients (incidence of wound complications 13.3% vs. 7.2%, respectively).
Patients with multiple or chronic comorbidities also were at greater risk of death in the year following bariatric surgery than were healthier patients. Their 30-day mortality was 1.5%, 90-day mortality was 5.8%, and 1-year mortality was 10.1%. Excluding patients with a diagnostic cost group score of 2 or more—a marker of health care utilization during the past year—from this cohort would have reduced the 90-day and 1-year mortality rates by approximately 20%, the investigators said.
Future research should compare the mortality risk of no surgery with that of bariatric surgery in superobese patients and in those with significant comorbidities, they added.
In an invited critique, Dr. Clifford W. Deveney of Oregon Health and Science University, Portland, noted that among study subjects who were superobese and had multiple concomitant disorders, 25% died during 3 years of follow-up. The study thus may have identified a subgroup of patients “in whom bariatric surgery may not offer a survival advantage,” he said (Arch. Surg. 2009;144:920).
This study was supported by the Department of Veterans Affairs. Neither Dr. Arterburn nor Dr. Deveney reported any financial conflict of interest.