Bariatric surgery is associated with reduced all-cause and CV mortality

Researchers from The Netherlands have reported that bariatric surgery is associated with reduced all-cause and cardiovascular (CV) mortality, and lowered incidence of several CV diseases in patients with obesity. The outcomes were reported in the paper, ‘Bariatric surgery and cardiovascular disease: a systematic review and meta-analysis’, published in the European Heart Journal.

The authors noted that although the effect of bariatric surgery on CV diseases (or CV mortality) has been published in four previous systematic reviews and meta-analyses, further prospective studies have since been published. Therefore, they carried out a comprehensive systematic review and meta-analysis of the available literature on the effect of bariatric surgery on CV disease and outcome.

In total, 39 studies were included in their systematic review. All the paper provided outcomes data regarding mortality and incidence of atrial fibrillation (AF), heart failure (HF), coronary artery disease/myocardial infarction and stroke. They did not identify any reports which have examined the effect of bariatric surgery on incident valvular heart disease such as aortic stenosis.

A total of 28 studies examined the effect of bariatric surgery on mortality, both all-cause and CV mortality. Following bariatric surgery, all-cause mortality varied from 0.0 to 23.7%, and 1.4 to 28.2% for controls, with follow-up duration ranging between 2 and 24 years. There were 21 studies that examined all-cause mortality, and reported adjusted HRs, and were therefore suited for the meta-analysis.

The 21 studies included 133,524 patients after bariatric surgery and 263 478 obese controls. The meta-analysis revealed that patients who had undergone surgery had a pooled HR of all-cause mortality of 0.55 (95% CI 0.49–0.62, p<0.001), compared with obese subjects in the control group. The results that bariatric surgery also reduced CV mortality (HR 0.59, 95% CI 0.47–0.73, p<0.001).

A total of seven studies examined the effect of bariatric surgery on the incidence of AF, ranging from 0.8–12.4% in patients after bariatric surgery to 1.3–16.8% in control subjects. The overall effect in the meta-analysis was a non-significant reduction after bariatric surgery vs. controls with regard to the incidence of AF (HR 0.82, 95% CI 0.64–1.06, p=0.12).

Twelve studies examined the effect of bariatric surgery on the incidence of HF, ranging from 0.4 to 9.9% in patients following bariatric surgery, compared with 0.7–15.7% in controls. The pooled HR for incident HF following bariatric surgery vs. control subjects was 0.50 (95% CI 0.38–0.66, p<0.001).

Seven studies reported on incident myocardial infarction after bariatric surgery and controls, bariatric surgery was associated with a lower incidence of myocardial infarction when compared with controls (HR 0.58, 95% CI 0.43–0.76, p<0.001). The incidence of stroke was reported in nine studies and showed that bariatric surgery reduced the incidence of stroke (HR 0.64, 95% CI 0.53–0.77, p<0.001).

“In summary, the results of this systematic review and meta-analysis of 39 studies suggest that bariatric surgery reduces mortality and incidence of CV disease in patients with obesity compared with non-surgical treatment,” they concluded. “Bariatric surgery should therefore be considered in these patients.”

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