These studies cannot rule out the possibility that patients who have weight loss surgery might be healthier in ways that we cannot easily measure. Most of these studies have not looked at whether the age at which surgery makes a difference or not. This particular study was conducted to compare the risk of dying over the long term between patients who have weight loss surgery and similar patients who do not have weight loss surgery. The study’s participants involved over 13,000 adults with obesity who had weight loss surgery, and over 13,000 matched patients who were eligible for but did not have surgery during the study observation period. 

After five years of follow-up, there were 197 deaths in the surgical group and 340 deaths in the matched non-surgery group. This data translated to a 32% reduction in death risk during the study period for those who underwent surgery. The overall mortality in patients aged 55 years or older was 2.8% in surgical patients and 6.1% in patients who did not have surgery. It was 0.7% in surgical patients compared with 0.9% in patients who did not have surgery. After measurable differences between the surgical and nonsurgical patients were accounted for, patients aged 55 years or older had a 48% lower risk for dying than matched patients who did not have surgery.

Other differences that researchers did not account for between patients who had surgery and those who did not might be partly responsible for the variation in the observed risk for deaths attributed to surgery. In conclusion, bariatric surgery has a lower risk of dying over the long term, and this benefit might be greater for those who have surgery at older ages.

Ref: https://www.acpjournals.org/doi/10.7326/P20-0010