Espen Bjøri‘s PhD thesis looks at factors related to incident and recurrent deep vein thrombosis and pulmonary embolism.


  1. Hospitalization is a major trigger for recurrent venous thrombosis.

  2. The rate of recurrence is similar in hospital-induced and non-hospital-related venous thromboembolism.
  3. D-dimer levels could identify patients with low risk of recurrent venous thromboembolism.


Thesis: Triggers and risk factors of first and recurrent venous thromboembolism
Candidate: Esben Bjøri
Time: January 29, 2020 at 12:15
Place: UiT The Arctic University of Norway, MH Vest: Auditorium Cerebrum
Link to university website (in Norwegian)


(1) 20 % of patients with non-cancer and non-surgery related hospital-induced venous thromboembolism experience recurrence within the next five years. This is the same rate as for non-hospitalized patients. Cancer patients have a recurrency rate of 25 %, whereas the rate is just over 10 % in surgically treated patients.

The study includes information on nearly 34,000 persons who participated in one or more of the first six Tromsø surveys. They were followed from 1994 until the end of 2012. 822 had venous thromboembolism during follow-up, and 132 experienced a second event.

(2) The rates of recurrence and mortality after a first venous thromboembolism are particularly high the first year. All-cause mortality the first year was 24%, whereas the overall risk of recurrence was 7.2%. Both mortality and recurrence decreased rapidly after that.

The study follows 710 patients with venous thromboembolism for a median of 7.7 years. 333 died and 114 had a new event.

(3) D-dimer levels below 1500 ng/mL is linked to about half the risk of recurrent venous thromboembolism. In patients with unprovoked venous thromboembolism and patients with deep vein thrombosis, the relationship seems to be even stronger.

The study includes blood samples from 454 cancer-free patients with a first venous thromboembolism, followed for a median of four years.

(4) Even hospitalization without immobilization is a major trigger for venous thromboembolism. The risk is even further augmented in immobilized patients. The higher number of hospitalizations and the longer the hospital stay, the higher the risk.

530 cancer-free patients were included. 159 of them had been hospitalized within three months prior to the event. The odds of pre-event hospitalization was almost 10 times higher than during previous, event-free three month periods in the same individuals. Hospital stays with immobilization was nearly 20 times more common in the 90-days prior to the venous thromboembolism than in the control periods.


(1) Bjøri, E., Arshad, N., Johnsen, H. S., Hansen, J. B., & Braekkan, S. K. (2016). Hospital‐related first venous thromboembolism and risk of recurrenceJournal of Thrombosis and Haemostasis14(12), 2368-2375.

(2) Arshad, N., Bjøri, E., Hindberg, K., Isaksen, T., Hansen, J. B., & Braekkan, S. K. (2017). Recurrence and mortality after first venous thromboembolism in a large population‐based cohort. Journal of Thrombosis and Haemostasis15(2), 295-303.

(3) Bjøri, E., Johnsen, H. S., Hansen, J. B., & Braekkan, S. K. (2017). D‐dimer at venous thrombosis diagnosis is associated with risk of recurrenceJournal of Thrombosis and Haemostasis15(5), 917-924.

(4) Bjøri, E., Johnsen, H. S., Hansen, J. B., & Brækkan, S. K. (2019). Hospitalization as a trigger for venous thromboembolism–Results from a population-based case-crossover studyThrombosis research176, 115-119.

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