Reduction of Cardiovascular Risk
after Bariatric Surgery

Are you suitable for bariatric surgery? | Benefits of Surgery | The vicious cycle of obesity |
Type II DM Control after Bariatric Surgery | Reduction of Cardiovascular Risk after Bariatric Surgery |
Metabolic Syndrome

Obesity has been known as a risk factor for diabetes, cardiovascular diseases, cancer and overall mortality. It is often suggested that weight loss may protect the patients against these conditions. However, there has been a lack of robust data to support the theory. As such, The Swedish Obese Subjects (SOS) study has been conducted to observe the effect of bariatric surgery on overall mortality, cardiovascular diseases, cancer and diabetes. [1]

The Swedish Obese Subjects (SOS) study is an ongoing, nonrandomized, prospective, controlled study. 4047 obese subjects were recruited, among them, 2010 were recruited in the surgery group, who underwent bariatric surgery and the rest 2037 subjects received conventional treatment (matched control group). Three types of bariatric surgery were performed, including gastric banding, vertical-banded gastroplasty and gastric bypass.

Overall mortality [2]

Figure 1 below depicts the overall mortality rate in a period of 16 years. Within the follow up period, 129 (6.3%) of the subjects in the control group deceased, comparing with 101 (5.0%) in the surgery group, given that no significant interactions was found between the subjects and their associated variables, such as sex, BMI, age, presence or absence of diabetes and previous cardiovascular events.

Figure 1

[1] Sjostrom L. JAMA 2013; 273: 219-234
[2] Sjostrom L, et al. JAMA 2012; 307:1
[3] N Engl J Med 2007; 357:753-761

Reduced cardiovascular events [3]

In a newly released SOS study data, within all the mortality recorded during the 18 years of follow up, cardiovascular events contributed to the greatest number of death, accounted for 49 of the subjects in the control group and 28 in the surgery group. Myocardial infarction, sudden death and cerebrovascular damage were the most common cardiovascular causes of death in the study. Bariatric surgery was proved to be associated with reduced number of fatal cardiovascular deaths, total cardiovascular events, fatal MI, total MI incidence, as well as total stroke events.

Figure 2

Long term mortality [4]

In a retrospective cohort study, the long-term mortality were determined from 9949 severely obese patients (BMI ≥ 35) who had undergone gastric bypass surgery from 1984-2002. The average follow-up time is 7.1 years. Significant long-term mortality reduction, as compared with the control group, was noted from the adjusted long-term mortality from any cause in the surgery group, which has decreased by 40%. Moreover, similar effect has been observed in the cause-specific mortality in the surgery group, which is 56%, 92% and 60% decrease for coronary artery disease, diabetes and cancer respectively.

It is evident that long-term total mortality can be reduced significantly after bariatric surgery, particularly for causes of death such as coronary artery disease, diabetes and cancer.

Quality of Life (QOL) [5]

In a population-based study, 148 patients after Roux-en-Y gastric bypass surgery were compared with 88 non-operative responders. The survey was conducted for about 4 years, consisting of three measurements, single-item overall quality-of-life items (Linear Analogue Self-Assessment Questionnaire; LASA), follow-up quality of life (Short-Form-12), and activity (Goldman’s Specific Activity Scale).

The result of the study has indicated that bariatric surgery is likely to cause long-term improvements in the quality of life and functional status in patients with severe obesity, especially for those with profound weight loss. In addition, this particular group of patients are more likely to seek treatment for depression, in order to improve their psychological state.

[3] Sjostrom L, et al. JAMA 2012; 307:1
[4] N Engl J Med 2007; 357:753-761
[4] Batsis JA, et al. AMJ 2009; 122: 11