Extreme Obesity Increases Risk for Death after Bariatric Surgery

David Arterburn, MD, MPH, from Group Health Research Institute in Seattle, Washington, and colleagues write, “The risk of death related to bariatric surgery is generally thought to be low…. Prior studies of bariatric surgery have primarily included younger female patients, so the mortality estimates from these studies might not apply to the older, predominantly male population that undergoes surgery at VA [Veterans Affairs] medical facilities.”

The goal of the study was to determine patient-related factors predicting mortality among obese veterans treated with bariatric surgery, with use of data from the VA National Surgical Quality Improvement Program. From January 1, 2000, through December 31, 2006, a total of 856 veterans had undergone bariatric surgery in 1 of 12 VA bariatric centers of the Group Health Center for Health Studies, the VA North Texas Health Care System, the Denver VA Medical Center, and the Durham VA Medical Center. Cox proportional hazards allowed estimation of the risk for death.

Before surgery, mean body mass index (BMI) was 48.7 kg/m², mean age was 54 years, and mean diagnostic cost group (DCG) score was 0.76. The study sample was 73.0% men, 83.9% white, and 7.0% American Society of Anesthesiologists class equal to 4. By the end of 2006, a total of 54 veterans (6.3%) had died.

The risk for death was increased in extreme obese patients (BMI > 50 kg/m²; hazard ratio [HR], 1.8; P = .04) or in those with a DCG score of 2 or greater (HR, 3.4; P < .001). There were 30 deaths in extreme obese patients (30-day, 90-day, and 1-year death rates of 2.0%, 3.6%, and 5.2%, respectively). Mortality rates in patients with a higher DCG score were 1.5%, 5.8%, and 10.1%, respectively.

“Extreme obese veterans and those with a greater burden of chronic disease had a greater risk of death after bariatric surgery from 2000 through 2006,” the study authors write.

Limitations of this study include older, predominantly male population; limited number of deaths; and lack of access to data on cause of death or changes in weight after surgery.

“The results of this study should inform discussions with patients with regard to the potential risks and benefits of bariatric surgery,” the study authors conclude. “These findings also suggest that the risks of bariatric surgery in patients with significant comorbidities, such as congestive heart failure, complicated diabetes and chronic obstructive pulmonary disease, should be carefully weighed against potential benefits in older male patients and those with extreme obesity.”

In an invited critique, Clifford W. Deveney, MD, from Oregon Health and Sciences University in Portland, notes that these findings correlate with those of other series studying the risk for death during the first year after gastric bypass surgery.

“Despite seeing increased mortality up to 1 year, others have demonstrated a clear survival benefit of bariatric surgery during 5 to 10 years, with survival advantage (operated on vs. not operated on) beginning at 6 months after surgery,” Dr. Deveney writes. “Therefore, despite the fact that the mortality rate increases during the postoperative period up to 1 year, it is small and does not negate the several advantages for patients who undergo bariatric surgery. However, there seems to be a group of patients (male, older, high morbidity scores) in whom bariatric surgery may not offer a survival advantage.”