Bariatric surgery reduces long-term risk of deep vein thrombosis: Study

London, UK: Bariatric or weight loss surgery causes a significant reduction in thromboembolic events, driven by a reduction in deep vein thrombosis (DVT), finds a recent study published in the journal Annals of Surgery.

Obesity increases the risk of venous thromboembolic events (VTEs) including DVT and pulmonary embolism. The rising prevalence of obesity and its associated co-morbidities, including VTE, represent a growing public health issue. Also, surgery is a risk factor for VTE. The long-term effect of bariatric surgery on VTE is ambiguous. Osama Moussa, St Mary's Academic Unit, Imperial College London, London, UK, and colleagues evaluated the effect of bariatric surgery on long-term risk of VTEs in a large cohort of patients with obesity.

For the purpose, the researchers analyzed data from 8146 obese patients, including 4073 who had undergone bariatric surgery and 4073 matched controls. They were followed for a median of 10.7 years.

The primary endpoint was the occurrence of VTEs; secondary endpoints were the occurrence of deep vein thrombosis alone, pulmonary embolism alone.

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Key findings of the study include:

• The adjusted rates of VTE were significantly lower in the bariatric surgery group (1.7%) than in the control group (4.4%), with a number needed to treat (NNT) to prevent 1 VTE of 37.


• The difference was driven by significant differences in DVT events (1.1% after bariatric surgery versus 3.4% among controls), whereas the rate of pulmonary embolism events did not differ significantly between the groups.


• All-cause mortality was significantly lower in the bariatric surgery group (1.3%) than in the control group (4%).


• The strongest reduction in VTE risk was observed in patients with class II obesity (BMI 35-40), with a smaller effect in patients with class I obesity (BMI 30-35), and no significant reduction in patients with class III obesity (BMI above 40).

"Overall, this study adds to the rapidly growing pool of evidence that highlights the wide-ranging metabolic, clinical, and lifestyle benefits of bariatric surgery for the management of patients with obesity and provides new knowledge regarding its effect on lowering long-term VTEs in this high-risk population," the researchers conclude.

The study, "Long-term Impact of Bariatric Surgery on Venous Thromboembolic Risk," is published in the journal Annals of Surgery.

DOI: 10.1097/SLA.0000000000003750