Severely obese older men who undergo bariatric surgery do not have a lower risk of death, researchers from Durham VA Medical Center, N.C. reported in the Journal of the American Medical Association (JAMA). There are two main types of bariatric surgery - gastric bypass, which is a permanent reduction in the size of the stomach, or gastric banding, a band is inserted and restricts the size of the opening from the esophagus to the stomach.
The authors wrote as background information:
"Obesity incidence has stabilized after decades of rapid increases, whereas the prevalence of patients with a body mass index (BMI) greater than 35 increased 39% between 2000 and 2005, the prevalence of severe obesity (BMI greater than 40) increased 50%, and the prevalence of superobesity (BMI >50) increased 75%.
Obesity is difficult to treat, and bariatric surgery is the most effective means to induce weight loss for the severely obese. Consequently, obesity surgery rates rapidly increased in tandem, To date, no study to our knowledge has examined the long-term survival of high-risk patients who underwent bariatric surgery."
Matthew L. Maciejewski, Ph.D., and team wanted to find out whether bariatric surgery might be linked to reduced mortality among mainly older high-risk men at 12 Veterans Affairs medical centers. They gathered data on 850 veterans. They had all undergone bariatric surgery between January 2000 through December 2006. They were aged 49.5 years (average) and had an average BMI of 47.4. They were compared with 41,244 controls who had not undergone surgery, average age 54.7 years with a BMI of 42 (average) from the same Veteran Affairs medical centers.
All of them were followed-up until December 2008.
Below are some highlighted data from their findings (crude mortality rates):
- 1.29% (11) of the 850 who had undergone surgery died within 30 days of the their operation
- After 1 year 1.5% of the bariatric surgery patients died, versus 2.2% of the controls
- At 2 years 2.2% of the bariatric surgery patients had died, versus 4.6% of the controls
- At 6 years 6.8% of the bariatric surgery patients died, compared to 15.2% of the controls
The scientists wrote:
"Our results highlight the importance of statistical adjustment and careful selection of surgical and nonsurgical cohorts, particularly during evaluation of bariatric surgery according to administrative data. Previous studies claiming a survival benefit for bariatric surgery had limited clinical information to conduct detailed risk adjustment or matching.
The survival differences between the bariatric surgery and control groups were modest in most previous studies, so the beneficial effects of surgery may have been attenuated if adjustment for confounders had been possible. We demonstrated that risk adjustment with regression analysis resulted in a significant association of surgery and survival that was reduced when equivalence in baseline characteristics improved via propensity matching in this high-risk patient group."
Even after being told that mortality is unlikely to be significantly altered after bariatric surgery, many patients may still go for it, because of the resulting weight loss, fewer co-existing illnesses and improved quality of life, the authors added.
"Survival Among High-Risk Patients After Bariatric Surgery"
Matthew L. Maciejewski, PhD; Edward H. Livingston, MD; Valerie A. Smith, MS; Andrew L. Kavee, MA; Leila C. Kahwati, MD, MPH; William G. Henderson, PhD, MPH; David E. Arterburn, MD, MPH
JAMA. Published online June 12, 2011. doi: 10.1001/jama.2011.817
Written by Christian Nordqvist