Study Suggests Bariatric Surgery Compared to Usual Care May Lower Mortality Rates among Obese Veterans

BACKGROUND:
Bariatric surgery is associated with improved weight, obesity-related comorbidities, and quality of life among severely obese adults. In addition, there is accumulating evidence that bariatric surgery is associated with better short-term survival than usual care, but there is little evidence about long-term survival. This retrospective cohort study examined long-term survival in a large multi-site cohort of obese Veterans who underwent bariatric surgery compared to matched controls. Using data from VA's Surgical Quality Improvement Program, investigators identified 2,500 Veterans (74% male) who underwent bariatric surgery in VA bariatric centers from 1/00 through 9/11, and matched them to 7,462 control patients. The main outcome was all-cause mortality through December 2013. All-cause mortality was compared between surgical and matched control patients using analysis adjusted for baseline covariates, including age, body mass index, marital status, free VA care due to disability or low income, and comorbidities (e.g., hypertension, depression, coronary artery disease). Investigators also conducted analyses of effect modification by sex, diabetes diagnosis, period of surgery (2000-2005 vs. 2006-2011), or super-obesity.

FINDINGS:

• When compared to matched control patients who did not have the surgery, obese Veterans who underwent bariatric surgery in the VA healthcare system had lower all-cause mortality starting at 5 years and up to 14 years following the procedure.
• After a mean follow up of 6.9 years in the surgical group and 6.6 years in the matched control group, there were a total of 263 deaths and 1,277 deaths, respectively, at the end of the 14-year study period. Study analyses estimated 1-year, 5-year and 10-year mortality rates that were 2.4%, 6.4% and 13.8% for Veterans who underwent bariatric surgery, and 1.7%, 10.4% and 23.9% for Veterans who did not undergo bariatric surgery.
• There were no significant differences in the association of bariatric surgery on mortality found across groups defined by sex, diabetes diagnosis, period of surgery, or super-obesity.

LIMITATIONS:

• These analyses cannot address unobserved confounding that might persist after matching because this was a retrospective, non-randomized study design rather than a randomized trial.
• Comorbid health conditions were identified using ICD-9 diagnosis codes, which do not account for severity.

IMPLICATIONS:

• These study results provide further evidence for the beneficial association between surgery and survival that has been demonstrated in younger, predominantly female, non-VA populations.

AUTHOR/FUNDING INFORMATION:
This study was funded by HSR&D (IIR 10-159), and Dr. Maciejewski was supported by an HSR&D Research Career Scientist Award. Drs. Olsen, Smith, Yancy, Weidenbacher, and Maciejewski, and Ms. Van Scoyoc are part of HSR&D's Center for Health Services Research in Primary Care, Durham, NC.

Arterburn D, Olsen M, Smith V, Livingston E, Van Scoyoc L, Yancy W, Eid G, Weidenbacher H, and Maciejewski M. Association between Bariatric Surgery and Long-Term Survival. JAMA. January 6, 2015;313(1):62-70.