Dr. Gregory Weiss reflects on data related to bariatric surgery and its subsequent impact on cardiovascular health.
Obesity may be the most detrimental health problem of the modern era. Over the past half-century, the global burden of obesity and its effect on global health, in particular, the growing incidence of cardiovascular disease (CVD) has increased exponentially.1
Beyond the direct association between obesity and CVD, it is known to be linked to other major risk factors such as hyperlipidemia, insulin resistance, and hypertension.2 The ultimate goal for both primary and secondary prevention of CVD in obese patients is weight reduction. The three major methods for weight loss are: pharmacologic or medical treatments, dietary and lifestyle modifications, and bariatric or weight loss surgery.
To spite a reasonable body of evidence that bariatric surgery works, controversy remains. After the initial weight loss, do patients realize long-lasting reductions in CV risk? Many clinicians believe that the way to meaningful and long-term weight loss is through putting in the work rather than cutting corners with a fast fix and there may be something to be said for developing healthy, long-lasting habits. Thankfully data exist that answers these questions.
Weight loss in the obese population has been studied extensively. While strong evidence exists, that bariatric surgery is a more reliable method of weight reduction than either pharmacological or lifestyle methods interest has now shifted to whether or not weight reduction surgery leads to long-term reductions in obesity-related comorbidities.3
In a recent nested cohort study performed by Osama Moussa and colleagues in the United Kingdom a clear association was found between bariatric surgery with lower long-term risk for major cardiovascular events (MACE) and heart failure in obese patients.2
In another retrospective, matched, controlled cohort study Dr. Singh and colleagues, also in the UK, looked at specific risk factors for CVD after bariatric surgery and found a reduced risk of hypertension, heart failure, and mortality when compared to medical management.4 Singh further found that patients with type 2 diabetes mellitus who underwent bariatric surgery also had a lower incidence of atrial fibrillation.4 In yet another recent study published in Current Opinion in Lipidology, Zohaib Iqbal, a biologist in Manchester, UK found that bariatric surgery led to improvements in obesity-related metabolic comorbidities including dyslipidemia, HDL functionality, hypertension, type 2 diabetes mellitus, insulin resistance, and inflammation.5
A major study out of the Cleveland Clinic sought to put to rest further questions about the efficacy of weight reduction surgery and the long-term implications with regards to MACE. Ali Aminian, MD, reports in the Journal of the American Medical Association that among patients with type 2 diabetes and obesity, bariatric surgery led to a significantly lower risk of incident MACE when compared to non-surgical treatment.6 An interesting caveat to these data appeared in another prominent article published this year in The American Journal of Cardiology showing that while MACE is reduced both short-term and long-term in the general bariatric population, obese patients with concomitant coronary artery disease (CAD) that underwent weight reduction surgery realized an increase in MACE events over time.7
From these data, it is clear that bariatric surgery offers lasting benefits to obese patients, especially those suffering from type 2 diabetes with regards to CV risk reduction and long-term MACE. However, do the benefits outweigh the risks of surgery? Here are some statistics. The average three-year weight loss following bariatric surgery is 62% of excess weight.8 Short-term and long-term mortality rates are 0.5% and 5% respectively.9,10 In a landmark study known as the Swedish Obese Subjects (SOS) study, more than 2000 patients undergoing bariatric surgery with more than 20 years of follow-up realized a 29% reduction in mortality irrespective of the amount of weight lost.11
The verdict is in. While more prospective randomized studies may be needed the available evidence suggests that there are undeniable, substantial, and sustainable benefits to weight reduction surgery over traditional weight-loss strategies in obese patients with regards to long-term cardiovascular risk and the incidence of MACE. Armed with this information clinicians can have a frank discussion with patients about weight reduction surgery and if it is right for them.