Study Summary

This retrospective case–control study investigated the relationship between metabolic surgery and MACE among patients with type 2 diabetes and obesity. Patients who underwent metabolic surgery (n = 2,287) were matched with control individuals (n = 11,435). The primary outcome was the incidence of MACE (all-cause mortality, coronary artery events, cerebrovascular events, heart failure, diabetic nephropathy, and atrial fibrillation). During follow up (median 3.9 years), the cumulative incidence of the primary endpoint was 30.8% in the surgical group and 47.7% in the control group (HR 0.61; P <0001). All-cause mortality occurred in 10.0% of patients in the surgical group and 17.8% of patients in the control group (adjusted HR 0.59; P <0.001).

Commentary

Study Strengths: This study is the first to focus on the association between bariatric surgery and cardiovascular outcomes in a high-risk population. Patients were older, had more comorbidities, and more insulin use than those in previous studies. Interestingly, the incidence of all of the six prespecified outcomes was significantly lower in the surgery group. The high event rates in the control group were similar to those previously reported in randomized trials of this population.

Study Limitations: The results of this retrospective, observational study can only be hypothesis-generating. A randomized trial will be needed to measure cofounders that could have influenced the findings. We can only conclude that there is an association between bariatric surgery and MACE in this patient population and cannot infer causality. The use of electronic health record codes raises the possibility of coding errors, misdiagnosis, and misclassification of outcomes.

Next Steps/Clinical Perspective: The results from this study are promising and could help guide selection of patients for whom bariatric surgery is likely to significantly improve cardiovascular outcomes.

Trial Reference

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Aminian  A, Zajicheck  A, Arterburn  AA, et al. Association of metabolic surgery with major adverse cardiovascular outcomes in patients with type 2 diabetes and obesity. JAMA[JAMA and JAMA Network Journals Full Text] doi: 10.1001/jama.2019.14231.