Venous thromboembolism (VTE) has long been considered an acute disease, but a new study and accompanying editorial explore whether it should be considered a chronic illness. Patients who’ve experienced deep vein thrombosis (DVT) or pulmonary embolism (PE) after surgery, trauma, or a period of immobility are typically treated with anticoagulation therapy for 3-6 months. Still, some patients encounter idiopathic VTE and have a high recurrence risk, “exceeding 50% over 10 years, if not treated with extended-duration anticoagulation,” reports a newly published Clinical Chemistry editorial, “Is Venous Thromboembolism a Chronic Inflammatory Disease?

In fact, “even patients who suffer VTE in the setting of identifiable provoking factors have an enduring risk of recurrence that exceeds 20% over 10 years,” wrote the editorial’s authors, Gregory Piazza and Paul M. Ridker. One analysis found that Danish patients with VTE had an increased risk of mortality during a 30-year follow-up period and that recurrent PE was an important cause of death during that time. Having patients with idiopathic VTE undergo low-intensity anticoagulation therapy with warfarin dramatically reduces the risk of recurrent problems, compared with putting them on anticoagulation therapy for a limited time. “These data support the hypothesis that VTE is a chronic disease with pathophysiology rooted in enduring as well as transient risk factors,” Piazza and Ridker wrote.

A study also published in the February issue of Clinical Chemistry adds new insight into the role of inflammation in VTE. In it, the authors reported finding a possible link between the development of DVT and rheumatoid factor, an inflammatory biomarker. The researchers analyzed data from the Copenhagen General Population Study and the Copenhagen City Heart Study to assess whether increased concentrations of rheumatoid factor increased the risk of VTE in people who did not have overt autoimmune disease. “During 368,381 person-years of follow-up in these 2 Copenhagen cohorts, 670 patients developed DVT and 539 developed PE. Compared with a rheumatoid factor concentration of ≤100 IU/mL, a concentration ≥ 100 IU/mL was strongly associated with DVT, with multivariable adjusted hazard ratios of 9.0 for 1-year follow-up, 4.3 for 5-year follow-up, and 3.1 for up to 32 years of follow-up,” according to the editorial.

“The current study adds to the body of evidence supporting inflammation as a critical component in the pathophysiology of venous thrombosis,” wrote Piazza and Ridker. “Additional evidence for the hypothesis that VTE is a chronic inflammatory disease may come from large completed and ongoing randomized controlled trials aimed to reducing thrombotic events by modulating inflammation.”

Additionally, the new findings provide “incremental evidence supporting the hypothesis that chronic systemic inflammation may precede incident VTE,” the editorial concludes.