Bariatric surgery was associated with a significantly reduced risk of cardiovascular disease (CVD) compared with nonsurgical care in patients with severe obesity and nonalcoholic fatty liver disease (NAFLD), a large retrospective study showed.
In a cohort of nearly 87,000 patients, bariatric surgery was linked with a 49% lower risk of CVD versus nonsurgical care (adjusted HR 0.51, 95% CI 0.48-0.54), reported Vinod K. Rustgi, MD, MBA, of Rutgers Robert Wood Johnson Medical School in New Brunswick, New Jersey, and colleagues.
At 96-month follow-up, 1,568 patients in the bariatric surgery group had incident cardiovascular events compared with 7,215 in the nonsurgical group, for an incidence rate difference of 4.8 per 100 person-years, they noted 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 composite CVD outcomes, including secondary ischemic heart events, transient ischemic attack, secondary cerebrovascular events, arterial embolism and thrombosis, and atherosclerosis (aHR 0.50, 95% CI 0.46-0.53).
“The findings provide evidence in support of bariatric surgery as an effective therapeutic tool to lower elevated CVD risk for select individuals with obesity and NAFLD,” Rustgi and team concluded. “Although bariatric surgery is a more aggressive approach than lifestyle modifications, it may be associated with other benefits, such as improved quality of life and decreased long-term health care burden.”
Of note, the cumulative incidences of cardiovascular events were higher among nonsurgical patients compared with surgical patients at several 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 outcome was lower in the surgical group compared with the nonsurgical 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 U.S., affecting over 30% of adults, Rustgi’s group noted. The prevalence of NAFLD increases with body mass index and is highest among those with severe obesity. If left untreated, NAFLD can lead to liver cirrhosis and liver cancer; however, there are no approved pharmacologic treatments for NAFLD. Lifestyle modifications are recommended, though the authors noted that they are often “difficult to sustain.”
Since NAFLD and CVD share common risk factors, “interventions that target NAFLD-associated obesity could potentially reduce CVD risk in this patient group,” they added.
Andrew Talal, MD, MPH, of the University at Buffalo in New York, who was not involved in this study, told MedPage Today that “this study adds important information for the benefits of bariatric surgery.”
“In prior work, bariatric surgery has [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.
This study was indirectly supported by postdoctoral funding and internal funding from the Robert Wood Johnson Medical School and the Ohio State University Comprehensive Cancer Center.
Rustgi reported no conflicts of interest.
A co-author reported funding from the National Center for Advancing Translational Sciences during this study.