Weight regain after bariatric surgery does not increase long-term mortality
Presenter: Markku Peltonen, PhD, Professor, Finnish Institute for Health and Welfare, Chronic Disease Prevention Unit
Peltonen M, Sjoholm K, Ahlin S, et al. Weight loss and regain after bariatric surgery in relation to long-term mortality and morbidity. Presentation at Obesity Week, October 14–17, 2023, Abstract Oral-062.
Obese patients who regained more than 20% of their maximal weight loss within 4 years after bariatric surgery had a similar mortality rate compared with those who kept their weight off, according to an analysis of the Swedish Obesity Study presented by Markku Peltonen, PhD, Professor, Finnish Institute for Health and Welfare, Chronic Disease Prevention Unit.1
Background. Weight loss after bariatric surgery usually peaks after 1 year, followed by a gradual weight regain. Most large and long-term epidemiologic studies have indicated that obesity is associated with increased mortality, and the life expectancy of severely obese persons is reduced by an estimated 5 to 20 years.2
Overall, as reported in 2007, the prospective, controlled Swedish Obese Subjects study3 involved 4,047 obese patients, including 2,010 who underwent bariatric surgery and a matched control group consisting of 2,037 patients who received conventional treatment. The study reported on overall mortality during an average of 10.9 years of follow-up.
The average weight change in control subjects was less than 2% during the period of up to 15 years during which weights were recorded. Maximum weight losses in the surgical subgroups were observed after 1 to 2 years: 32% with gastric bypass, 25% with vertical-banded gastroplasty, and 20% with banding. After 10 years, the weight losses from baseline were stabilized at 25%, 16%, and 14%, respectively.
The unadjusted overall hazard ratio was 0.76 in the surgery group compared with the control group, and the hazard ratio adjusted for sex, age, and risk factors was 0.71. The researchers concluded that bariatric surgery for severe obesity is associated with long-term weight loss and decreased overall mortality, and they suggested that it may be a favorable option for treating severe obesity.
Current study. The researchers set out to evaluate whether the degree of initial weight loss and subsequent rapid vs slow regain correlated with long-term mortality and morbidity rates. Included were 1,348 patients from the surgery group of the Swedish Obese Subjects study. They were divided into 4 categories according to how much weight they had lost at 1 year (large vs small initial weight loss) and then according to how rapidly they regained weight between years 1 and 4. Information on mortality and morbidity were obtained from national registries. Cox proportional hazard models were used to analyze time to events.
At 1 year, the large–weight-loss group had lost approximately 32% of their body weight, while the small– weight-loss group had lost 17%. Weight changes between years 1 and 4 were 1.9% and 19.5% in the slow vs rapid regain groups for those with large initial weight loss, and –2.3% and 11.5%, respectively, for those with small initial weight loss.
Among those in the large initial weight-loss group, mortality rates were 11.6 per 1,000 person-years in the slow-regain group vs 10.9 per 1,000 person-years in the rapid-regain group (adjusted hazard ratio [HR] 1.08, 95% confidence interval 0.81–1.43), P = .611.). For those with small initial weight loss, the corresponding rates were 13.9 vs 12.8 per 1,000 person-years (adjusted HR 1.10, (95% CI 0.83–1.45), P = .510.).
Rates of cardiovascular disease and cancer were similar in the weight loss and regain groups, said Dr. Peltonen. The microvascular disease rate was lowest in the group with large initial weight loss and slow regain, and highest in the group with small initial weight loss and rapid regain.
Dr. Peltonen concluded: “There were no marked differences in total mortality over the 26-year follow-up in persons experiencing rapid vs slow regain in weight after bariatric surgery, and this was independent of the degree of initial weight loss.”
References
- Peltonen M, Sjoholm K, Ahlin S, et al. Weight loss and regain after bariatric surgery in relation to long-term mortality and morbidity. Presentation at Obesity Week, October 14–17, 2023, Abstract Oral-062.
- Fontaine KR, Redden DT, Wang C, Westfall AO, Allison DB. Years of life lost due to obesity. JAMA 2003; 289(2):187–193. doi:10.1001/jama.289.2.187
- Sjöström L, Narbro K, Sjöström CD, et al. Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl J Med 2007; 357(8):741–752 doi:10.1056/NEJMoa066254
Disclosures
Dr. Peltonen reported no disclosures.