Abstract 4123814: Long-term Incidence of Cardiovascular Events and Mortality in Patients with and without Weight Regain After Bariatric Surgery in the Swedish Obese Subjects Study

Background: Obesity shortens life expectancy, while bariatric surgery causes large weight loss and increases median life expectancy by approximately 3 years. However, weight regain after bariatric surgery is common, and its impact on health remains uncertain. In this study, we examined whether weight regain following bariatric surgery is associated with long-term cardiovascular outcomes and mortality. Methods: We analyzed patients undergoing bariatric surgery in the prospective Swedish Obese Subjects study, aged 37-60 with a BMI≥34 (men) or ≥38 (women), recruited 1987-2001. Patients who regained ≥20% of their 1-year weight loss after 4 years (regain group; n=715) were compared to those who regained less (maintenance group; n=631). Information on cardiovascular disease as well as overall and cardiovascular mortality was obtained from the Swedish Population and Address Register, the Swedish Cause of Death Register, and the Swedish National Patient Register. Median follow-up was 27 years. Results: Average weight change from year 1 to year 4 was +12.8 kg and -0.2 kg in the regain and maintenance groups, respectively. The incidence of major adverse cardiovascular events (myocardial infarction, stroke and heart failure) was similar between the groups, with 185 events in the regain group and 137 in the maintenance group. This corresponds to 11.6 events per 1000 person-years (95% CI: 10.1-13.5) for the regain group, and 10.0 events per 1000 person-years (95% CI: 8.3-12.4) for the maintenance group. The adjusted HR was 1.16 (95% CI: 0.92-1.46), p=0.213. During follow-up, there were 216 deaths in the regain group and 184 in the maintenance group, resulting in nearly identical overall mortality rates of 12.4 per 1000 person-years for both groups (95% CI for regain: 10.9-14.2, maintenance: 10.9-14.3). The number of deaths from cardiovascular disease was 77 in the regain group and 57 in the maintenance group, corresponding to similar incidence rates of 4.4 per 1000 person-years (95% CI: 3.5-5.5) and 3.8 per 1000 person-years (95% CI: 3.0-5.0), respectively (p=0.550). Conclusions: The incidence of major adverse cardiovascular events, as well as total and cardiovascular mortality, was similar between the weight regain and maintenance groups. This suggests that the beneficial association between bariatric surgery and reduced cardiovascular events persists despite weight regain.