Bariatric Surgery Associated with 3-Year Increase in Life Expectancy for Obese Patients

October 16, 2020

An analysis of a Swedish obesity study with more than 20 years of follow-up data is detailing differences in life expectancy among patients who undergo bariatric surgery versus those opting for usual care.

An analysis of data from an ongoing study in Switzerland is shedding light on the impact bariatric surgery can have on life expectancy compared to standard obesity care.

While neither group of patients achieved the life expectancy of the general population, results of the study suggest patients undergoing bariatric surgery lived a median of 3 years longer than their counterparts in the study’s control group.

“Our study shows that bariatric surgery prolongs (life expectancy) by three years. But even after surgery, patients still have a shorter life expectancy than the general population. That's why it's very important for bariatric patients to be offered adequate postoperative monitoring and follow-up," noted Lena Carlsson Ekander, MD, PhD, Professor of Clinical Metabolic Research at Sahlgrenska Academy, in a statement.

To learn more about the effects of treatment course on mortality in obese patients, Carlsson Ekander and a group of colleagues designed an analysis of the ongoing Swedish Obese Subjects (SOS) study. The SOS study, which recruited participants from September 1, 1987 through January 31, 2001, provided investigators with information related to 4047 obese patients and 1135 patients from the general population, which were used as a reference cohort.

Of the 4047, 2007 underwent surgery and 2040 were used as a control group. When the investigators performed their analysis on December 31, 2018, the median duration of follow-up was 24 (IQR, 22-27) years for patients in the surgery group, 22 (IQR, 21-27) years for patients in the control group, and 20 (IQR, 19-21) for patients in the reference group.

Of note, patients in the surgery group underwent banding (18%), vertical banded gastroplasty (69%), or gastric bypass (13%) procedures while those in the control group received conventional obesity treatment.

Upon analysis, investigators found 22.8% (n=457) of patients in the surgery group and 26.4% (n=539) of the control group died (HR, 0.77; 95% CI, 0.68-0.87; P <.001).Based on the results, investigators calculated the median life expectancy in the surgery group was 2.4 (95% CI, 1.3-3.5; P <.001) years longer than in the control group, with an adjusted difference of 3.0 years (95% CI, 1.8-4.2; P <.001) years.

However, investigators pointed out patients in the control group had a median life expectancy 5.5 (95% CI, 3.4-7.6; P < .001) than patients included in the reference cohort from the general population.

Further analysis indicated the most common causes of death were deaths from cardiovascular disease and cancers. Specifically, cardiovascular disease was responsible for 167 deaths in the surgery group and 221 deaths in the control group (HR, 0.70; 95% CI, 0.57-0.85) while cancers were responsible for 135 deaths in the surgery group and 165 deaths in the control group (HR, 0.77; 95% CI, 0.61-0.96).

“For the first time, we've got a measure of how much bariatric surgery prolongs life expectancy for the average patient. But it's important to point out that it's a matter of averages. Not all patients are the same, so you can't draw the conclusion that everyone who gets the operation done lives three years longer,” added Carlsson Ekander.

This study, “Life Expectancy after Bariatric Surgery in the Swedish Obese Subjects Study,” was published in the New England Journal of Medicine.