MedicalResearch.com Interview with:
David Arterburn, MD, MPH, FACP
Group Health Research Institute
Seattle, WA 98101 and
David L. Maciejewski PhD
Center for Health Services Research in Primary Care
Durham VA Medical Center, Durham, North Carolina
MedicalResearch.com: Why was this study needed?
Response: There were several reasons to conduct this study. First, although complications and death during and soon after bariatric surgery have progressively declined over the past several decades, there is simply very little long-term evidence on the survival benefits of bariatric surgery in Americans having surgical procedures that are being used today in routine practice.
Second, we felt that it was important to look at the impact of bariatric surgery among veterans because they represent an older male cohort often with multiple medical comorbidities, which is different from the typical bariatric patient in the United States, who is often younger and female.
MedicalResearch.com: How was your study conducted?
Response: We conducted a retrospective observational study using high-quality data from national Department of Veterans Affairs electronic databases and the VA Surgical Quality Improvement Program. We identified veterans who underwent bariatric surgery in VA medical centers from 2000 to 2011. Three quarters of them were men. We matched them to control patients using an algorithm that included age, sex, VA geographic region, body mass index (BMI), diabetes, and Diagnostic Cost Group. We then compared survival across bariatric patients and matched controls using Kaplan-Meier estimators and stratified, adjusted Cox proportional hazards analyses.
MedicalResearch.com: What were the main findings of your study?
Response: This study had three important results:
1) Our analysis showed no significant association between bariatric surgery and death from all causes in the first year of follow-up. In other words, having bariatric surgery was not significantly related to a veteran’s chance of dying in the first year compared to not having surgery.
2) We had an average follow-up of 6.9 years in the surgical group and 6.6 years in the matched control group. After one to five years, adjusted analyses showed significantly lower mortality in the patients who had surgery: 55% lower, with a hazard ratio of 0.45. The finding was similar at 5 or more years, with a hazard ratio of 0.47. This means that bariatric surgery was associated with lower long-term mortality – that is, better long-term survival among veterans, which is consistent with limited non-VA research that has addressed this same question.
3) Finally, we also found that the relationship between surgery and survival were similar comparing men and women, patients with and without diagnosed diabetes, and patients who had bariatric surgery before versus after year 2006.