Association of Bariatric Surgery With Cardiovascular Outcomes in Adults With Severe Obesity and Nonalcoholic Fatty Liver Disease

Question  Is bariatric surgery a factor in reducing the risk of cardiovascular outcomes in adults with severe obesity and nonalcoholic fatty liver disease (NAFLD)?Findings  In this large cohort study of 86 964 individuals with NAFLD and severe obesity, compared with nonsurgical care, bariatric surgery was associated with a 49% decrease in the risk of cardiovascular disease, a 47% decrease in the risk of primary composite cardiovascular events, and a 50% lower risk of secondary composite cardiovascular events.

Meaning  Findings of this study suggest that individuals with severe obesity and NAFLD who underwent bariatric surgery have a lower cardiovascular disease risk than those who received nonsurgical care.

Importance  There are no approved treatments for nonalcoholic fatty liver disease (NAFLD) despite its association with obesity and increased risk of cardiovascular disease (CVD).

Objective  To examine the association between bariatric surgery and CVD risk in individuals with severe obesity and NAFLD.

Design, Setting, and Participants  This large, population-based retrospective cohort study obtained data from the MarketScan Commercial Claims and Encounters database from January 1, 2007, to December 31, 2017. Participants included insured adults aged 18 to 64 years with NAFLD and severe obesity (body mass index ≥40) without a history of bariatric surgery or CVD before NAFLD diagnosis. Baseline characteristics were balanced between individuals who underwent surgery (surgical group) and those who did not (nonsurgical group) using inverse probability of treatment weighting. Data were analyzed from March 2020 to April 2021.

Exposures  Bariatric surgery (Roux-en-Y gastric bypass, sleeve gastrectomy, and other bariatric procedures) vs nonsurgical care.

Main Outcomes and Measures  The main outcome was the incidence of cardiovascular events (primary or secondary composite CVD outcomes). The primary composite outcome included myocardial infarction, heart failure, or ischemic stroke, and the secondary composite outcome included secondary ischemic heart events, transient ischemic attack, secondary cerebrovascular events, arterial embolism and thrombosis, or atherosclerosis. Cox proportional hazards regression models with inverse probability treatment weighting were used to examine the associations between bariatric surgery, modeled as time varying, and all outcomes.

Results  The study included 86 964 adults (mean [SD] age, 44.3 [10.9] years; 59 773 women [68.7%]). Of these individuals, 30 300 (34.8%) underwent bariatric surgery and 56 664 (65.2%) received nonsurgical care. All baseline covariates were balanced after applying inverse probability treatment weighting. In the surgical group, 1568 individuals experienced incident cardiovascular events compared with 7215 individuals in the nonsurgical group (incidence rate difference, 4.8 [95% CI, 4.5-5.0] per 100 person-years). At the end of the study, bariatric surgery was associated with a 49% lower risk of CVD (adjusted hazard ratio [aHR], 0.51; 95% CI, 0.48-0.54) compared with nonsurgical care. The risk of primary composite CVD outcomes was reduced by 47% (aHR, 0.53 [95% CI, 0.48-0.59), and the risk of secondary composite CVD outcomes decreased by 50% (aHR, 0.50; 95% CI, 0.46-0.53) in individuals with vs without surgery.

Conclusions and Relevance  Results of this study suggest that, compared with nonsurgical care, bariatric surgery was associated with significant reduction in CVD risk in individuals with severe obesity and NAFLD.