Bariatric surgery in NAFLD associated with a lower risk of heart disease

A large retrospective study showed that bariatric surgery was associated with a significantly reduced risk of cardiovascular disease (CVD) in patients with severe obesity and nonalcoholic fatty liver disease (NAFLD) compared to nonsurgical treatment.

In a cohort of nearly 87,000 patients, bariatric surgery was associated with a 49% reduced risk of cardiovascular disease compared to nonsurgical treatment (adjusted HR 0.51, 95% CI 0.48-0.54), reported Vinod K Rustgi, MD, MBA, from Rutgers Robert Wood Johnson Medical School in New Brunswick, NJ, and colleagues.

At 96 months of follow-up, 1,568 patients in the bariatric surgery group had cardiovascular events compared to 7,215 in the nonsurgical group, an incidence rate difference of 4.8 per 100 person-years, they found in JAMA network open.

Specifically, bariatric surgery was associated with a 47% lower cumulative incidence of primary composite CVD outcomes, including myocardial infarction, heart failure, and ischemic stroke (aHR 0.53, 95% CI 0.48-0.59), and a 50% lower cumulative incidence of secondary related composite CVD outcomes including secondary ischemic cardiac events, transient ischemic attack, secondary cerebrovascular events, arterial embolism and thrombosis and atherosclerosis (aHR 0.50, 95% CI 0.46-0.53).

“The results provide evidence to support bariatric surgery as an effective therapeutic tool to reduce the increased risk of CVD for selected individuals with obesity and NAFLD,” concluded Rustgi and his team. “Although bariatric surgery is a more aggressive approach than lifestyle changes, it may come with other benefits, such as: B. an improved quality of life and a reduced burden on long-term health care.”

Notably, the cumulative incidence of cardiovascular events was higher in nonsurgical patients than in surgical patients at multiple time points throughout the study:

• 24 months: 12.8% vs. 5.0%
• 48 months: 21.1% vs. 10.4%
• 72 months: 28.2% vs. 15.6%
• 96 months: 35.6% vs. 21.6%

At 96 months, the cumulative incidence of each primary endpoint was lower in the surgical group than in the non-surgical group:

• Myocardial infarction: 1.7% vs. 2.6%
• Heart failure: 4.2% vs. 11.5%
• Ischemic Stroke: 3.0% vs 3.4%

NAFLD is the most common chronic liver disease in the US, affecting over 30% of adults, Rustgi’s group found. The prevalence of NAFLD increases with body mass index and is highest in individuals with severe obesity. Left untreated, NAFLD can lead to liver cirrhosis and liver cancer; However, there are no approved pharmacological treatments for NAFLD. Lifestyle changes are recommended, although the authors noted that they are often “difficult to sustain.”

Because NAFLD and CVD share common risk factors, “interventions targeting NAFLD-associated obesity could potentially reduce CVD risk in this patient population,” they added.

Andrew Talal, MD, MPH, of the University at Buffalo in New York, who was not involved in this study, said MedPage today that “this study adds important information for the benefits of bariatric surgery.”

“In previous work, bariatric surgery [also[ been associated with long-term histological improvements in nonalcoholic steatohepatitis (NASH),” he added.

For this study, Rustgi and colleagues examined data on 86,964 patients with NAFLD and severe obesity (BMI ≥40) from the MarketScan Commercial Claims and Encounters database from January 2007 through December 2017. Of these patients, 34.8% underwent bariatric surgery, while 65.2% received nonsurgical care. Bariatric surgical procedures included Roux-en-Y gastric bypass (n=11,371), sleeve gastrectomy (n=10,404), and other surgeries (n=8,525).

Patient characteristics were balanced between groups using inverse probability treatment weighting. Mean patient age was 44.3, and 68.7% were women. Common comorbidities included hypertension (56-57%), dyslipidemia (45-46%), and obstructive sleep apnea (24-35%).

Surgical patients tended to be younger (mean age 43 vs 45), women (76% vs 65%), and less likely to have a history of smoking (6% vs 9%).

Rustgi and colleagues acknowledged that the use of claims data and the observational study design may have led to unmeasured confounding or potential misclassification. Furthermore, the results could not be stratified by CVD disease phenotype due to the absence of reliable non-invasive diagnostic methods for NAFLD.