Bariatric surgery increases life expectancy vs. usual obesity care
Life expectancy increased by 3 years for adults with obesity who had bariatric surgery compared with usual care; however, life expectancy was still shorter than that for the general population, according to researchers in Sweden.
“Studies have shown bariatric surgery is associated with reduced relative risk of mortality, but the extent to which this increases life expectancy has been unclear,” Lena M.S. Carlsson, MD, PhD, professor of clinical metabolic research at Sahlgrenska Academy, University of Gothenburg, Sweden, told Healio. “Now, for the first time, we have been able to estimate how much bariatric surgery prolongs life expectancy for the average patient. But it’s important to point out that patients are different, and our results indicate how many life-years are gained on average. The 3-year average increase in life expectancy can, therefore, not be translated into life-years gained for a specific patient.”
In a study published in The New England Journal of Medicine, Carlsson and colleagues analyzed mortality data from 2,007 adults with obesity who had banding, vertical banded gastroplasty or gastric bypass surgery (mean age, 47.2 years; 29.2% men) and 2,040 adults who received standard obesity care and served as a control group (mean age, 48.7 years; 29.1% men). All participants were recruited between Sept. 1, 1987, and Jan. 31, 2001, aged 37 to 60 years and had a BMI of at least 34 kg/m2 for men and 38 kg/m2 for women. Information on deaths was cross-checked with the Swedish Population and Address Register and against the Swedish Cause of Death Register. Data from the bariatric surgery and control groups were compared with a random sample of 1,135 adults aged 37 to 60 years in the Swedish Obese Subjects reference study conducted between 1994 and 1999 (mean age, 49.5 years; 46.2% men).
After adjusting for risk factors, individuals who had bariatric surgery had a lower mortality rate than the controls (HR = 0.7; 95% CI, 0.61-0.81; P < .001). There was also a lower mortality rate in the reference group compared with controls (HR = 0.38; 95% CI, 0.31-0.47; P < .001).
The surgery group had a longer adjusted median life expectancy than the control group (adjusted difference, 3 years; 95% CI, 1.8-4.2; P < .001). The reference group also had a longer life expectancy (adjusted difference, 8.5 years; 95% CI, 6.4-10.5; P < .001), meaning the surgery group had a median life expectancy 5.5 years shorter than that of the reference group.
The two most common causes of death in the study were from cardiovascular disease and cancer. Individuals who had bariatric surgery had a lower CVD mortality rate (HR = 0.7; 95% CI, 0.57-0.85) and a lower cancer mortality rate (HR = 0.77; 95% CI, 0.61-0.96) than the control group.
When compared with the reference group, those who had bariatric surgery had a higher rate of CVD deaths (HR = 2.64; 95% CI, 1.78-3.91) and deaths from non-CV causes (HR = 1.5; 95% CI, 1.18-1.91).
“Although bariatric surgery was associated with longer life expectancy compared to usual care, mortality remained higher than in the general population,” Carlsson said. “To obtain life expectancy similar to the general population, research is therefore needed to further increase life expectancy after bariatric surgery. This could include research to identify markers that can be used for precision medicine to classify patients that are considering bariatric surgery and recommend surgical treatment to those that are predicted to have large benefit. In our study, the treatment benefit was surprisingly similar in subgroups defined by risk factors such as BMI and classical cardiovascular risk factors.”
Carlsson added that future research should seek to identify genetic markers to help inform the decision process for undergoing bariatric surgery. She said it is also important to improve surgery follow-up to prevent conditions that are responsible for the remaining excess mortality in individuals who have undergone bariatric surgery.
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Lena M.S. Carlsson, MD, PhD, can be reached at email@example.com.