Low-grade inflammation and future risk of venous thromboembolism - does a relationship exist?

Inflammation is a risk factor for venous thromboembolism. We have investigated wheter a certain infammatory marker is associated with future venous thromboembolism.

Inflammation is a common feature for many of the known risk factors for venous thromboembolism, as seen in cancer, infections and autoimmune conditions. Low-grade inflammation can be seen in blood markers tested in the laboratory, without subjective symptoms. Long-standing, low-grade inflammation is a well-known risk factor for arterial thrombosis, as for example heart attack

Is this the case also for venous thrombosis?

Some inflammatory markers, such as C-reactive protein, has been previously studied, but studies have reach

ed conflicting conclusions. We therefore wanted to investigate whether another inflammatory marker, neutrophil to lymphocyte ratio (NLR), was associated with future venous thromboembolism.

NLR was calculated in more than 25 000 participants of the fourth Tromsø Study, conducted in 1994-95. All events of venous thromboembolism among the participants were recorded up to 2012. We found no association between NLR at baseline, and future risk of venous thromboembolism when followed up for 17 years. With a shorter follow-up time of 3 years, we found a more than doubled risk of venous thromboembolism in those with a high NLR.

We also looked at risk of recurrence, which is a second event of venous thromboembolism, but found no association between NLR measured in the Tromsø Study and risk of recurrent venous thromboembolism. What we did find, was higher mortality rates after the thromboembolic event in those with a higher NLR at baseline.

Adding the knowledge from this study on NLR and venous thromboembolism to previous studies on other inflammatory markers, we can conclude that longstanding, low-grade inflammation is not a risk factor for future VTE. Short-term inflammation, on the other hand, seems to be of importance for the risk of venous thromboembolism.


Reference: Grimnes G, Horvei LD, Tichelaar V, Brækkan SK, Hansen JB: Neutrophil to Lymphocyte Ratio And Future Risk Of Venous Thromboembolism And Mortality: The Tromsø Study. Haematologica 2016

Page administrator: Gro Grimnes
created: 20.02.2017 12:36