A study published in JAMA found that bariatric surgery significantly reduced the risk of major adverse cardiovascular events (MACE) in patients with type 2 diabetes.
In this retrospective, observational, matched-cohort study, researchers assessed 287,438 U.S. adult patients with diabetes from the Cleveland Clinic Health System between 1998 and 2017, of whom 2,287 underwent one of four metabolic surgeries at the Cleveland Clinic. These patients were matched 1:5 to 11,435 patients with diabetes and obesity (body mass index, ≥30 kg/m2) who did not undergo surgery. Patients were followed through December 2018.
MACE (primary endpoint) was defined as first occurrence of all-cause mortality, coronary artery events, cerebrovascular events, heart failure, nephropathy, and atrial fibrillation. Secondary endpoints included three-component MACE (myocardial infarction, ischemic stroke, and mortality) and the six individual components of the primary endpoint.
The overall median duration of follow-up was 3.9 years (interquartile range, 1.9-6.1 years). At the end of the study period, 385 patients in the surgical group and 3,243 in the non-surgical group experienced a MACE; the cumulative incidence at eight years was 30.8% in the surgical group (95% confidence interval [CI], 27.6-34.0) and 47.7% in the non-surgical group (95% CI, 46.1-49.2; P<0.001), for an absolute risk difference (ARD) of 16.9% (95% CI, 13.1-20.4; adjusted hazard ratio [HR], 0.61; 95% CI, 0.55-0.69).
All prespecified secondary outcomes showed statistically significant differences in favor of metabolic surgery, including mortality. All-cause mortality occurred in 112 patients in the surgery group and 1,111 in the non-surgical group; the cumulative incidence at eight years was 10.0% (95% CI, 7.8-12.2) and 17.8% (95% CI, 16.6-19.0), respectively (ARD, 7.8%; 95% CI, 5.1-10.2; adjusted HR, 0.59; 95% CI, 0.48-0.72).
In addition, mean body weight was reduced by 29.1 kg (95% CI, 28.8-29.3) in the surgery group versus 8.7 kg (95% CI, 8.6-8.9) in the non-surgical group (mean difference, 20.3 kg; 95% CI, 20.1-20.6]). Surgery was also associated with a significant reduction in glycated hemoglobin level (P<0.001).
Patients’ use of non-insulin diabetes medications, insulin, renin-angiotensin system blockers, other antihypertensive medications, lipid-lowering therapies, and aspirin were also significantly lower after metabolic surgery.
These findings must be confirmed by a randomized study, according to the authors.