medwireNews: The all-cause mortality benefits of Roux-en-Y gastric bypass (RYGB) surgery are predominantly driven by patients who have diabetes at the time of surgery, according to the results of an observational study.
The researchers matched 2428 RYGB patients to the same number of non-surgical control individuals by age, body mass index, gender, and diabetes status at the time of surgery.
They found that while RYGB patients experienced a significant 35% reduction in the risk for all-cause mortality compared with controls, further analysis found reduced mortality only among patients with diabetes at the time of surgery.
For the 625 RYGB patients with diabetes, the risk for all-cause mortality was reduced by 58%, compared with 8% for the 1803 RYGB patients without diabetes.
“This is the first study to demonstrate that all-cause mortality risk after RYGB is modified by baseline diabetes status,” the researchers report in Diabetes Care.
The procedure was also associated with an increased 2-year rate of complete remission from diabetes, at 38.6%, compared with 0.4% for non-surgical controls.
And complete remission, in turn, was associated with a significantly decreased rate of death, with a hazard ratio (adjusted for diabetes remission score) of 0.12. Similar results were found for individuals with partial plus complete remission.
Risks for specific causes of death varied among the groups with and without diabetes. Patients with diabetes who underwent RYGB compared with those who did not were significantly less likely to die from cardiovascular diseases, respiratory conditions, and diabetes, while patients without diabetes undergoing the procedure were less likely to die of cancer and respiratory conditions than those who did, but were more likely to die from external causes.
Michelle R Lent (Geisinger Clinic, Danville, Pennsylvania, USA) and colleagues comment that “changes in the absorption of substances and medications, the potential for addiction transfer from food to substances, as well as numerous psychosocial factors that can change after surgery may contribute to the elevated risk of death from external causes.”
Therefore, they suggest that “some patients may benefit from a higher level of care postoperatively to remain safe.”
Overall, the researchers conclude: “These data demonstrate a strong, long- term protective effect of bariatric surgery for patients with diabetes but no significant all-cause mortality risk reduction for patients without diabetes.”
But they add that “patients [without diabetes] can still benefit from the other well-documented benefits of RYGB, including better quality of life.”
By Catherine Booth
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