Bariatric Surgery-Associated VTE Risk Decreases in Long Term

TOPLINE:

Although bariatric surgery poses a high risk for venous thromboembolism (VTE) in the initial postoperative month, this risk decreases significantly over time.

METHODOLOGY: 

• Bariatric surgery is linked to a short-term increased risk for VTE, including pulmonary embolism (PE) and deep vein thrombosis (DVT), but whether this risk is sustained in the long term after surgery is not well defined.
• Researchers used data from three regions of the Kaiser Permanente integrated healthcare system to evaluate the long-term risk for incident VTE in 30,171 patients with severe obesity (body mass index, ≥ 35) who underwent a bariatric procedure and 218,961 matched controls who did not.
• The primary outcome was the first occurrence of VTE, identified using the International Classification of Diseases, Ninth Revision codes for PE and/or DVT.
• The secondary outcome was the risk for incident PE with or without DVT.
• The date of surgery was considered the index date for patients undergoing bariatric surgery, whereas for those not undergoing surgery, the index date was determined by the date of surgery of their matched counterparts. Patients were followed for a median of 9.3 years.

TAKEAWAY:

• At 30 days post-index date, patients who underwent bariatric surgery were at a fivefold higher risk for any VTE (adjusted hazard ratio [aHR], 5.01) and fourfold higher risk for PE (aHR, 3.93) than those who did not undergo surgery (P
• However, the risk for VTE was 48% (aHR, 0.52; P P
• Similarly, the risk for PE was reduced by 70% (aHR, 0.30; P P
• In a sensitivity analysis, the aHR estimates for any VTE were 11.93, 0.50, and 0.64 at 30 days, 1 year, and 5 years post-index date, respectively, suggesting a shift toward a lower risk for VTE in the long term.

IN PRACTICE:

“As patients and their clinicians weigh the risks and benefits of bariatric surgery, our finding provides additional evidence to consider not only the procedure’s risks in the short term but to balance these with potentially strong long-term benefits,” the authors wrote.

SOURCE:

The study, led by Laura B. Harrington, PhD, MPH, Kaiser Permanente Washington Health Research Institute, Seattle, was published online in Obesity Surgery.

LIMITATIONS:

Overall, 29%-35% of participants were lost to follow-up at 5 years. Data regarding the indication for anticoagulation use at or before the index date were not available. Moreover, the causal inference and possible confounding factors may have persisted despite model adjustment for various risk factors for VTE owing to the observational nature of the study.

DISCLOSURES:

The study was supported by the National Institutes of Health/National Institute of Diabetes and Digestive and Kidney Diseases. A few authors reported receiving research grants, reimbursements for travel expenses, and stipends for reviewing grants outside of the submitted work.