Cand.med Esben Bjøri disputerer for ph.d.-graden i Helsevitenskapelige fag og vil offentlig forsvare avhandlingen:
«Triggers and risk factors of first and recurrent venous thromboembolism”
Kort populærvitenskapelig sammendrag av avhandlingen:
Venous thromboembolism (VTE), encompassing both deep vein thrombosis and pulmonary embolism, is a major public health concern due to substantial morbidity and mortality. Around 50% of all VTE cases are hospital-related, and hospital-acquired VTE is considered a leading cause of VTE-related deaths. Importantly, VTE also has life-long implications, as a large proportion of VTE-patients suffer either a recurrent event or VTE-related chronic complications. The first aim of the thesis was to investigate hospitalization as a trigger factor for incident VTE. Secondly, we aimed to provide new insights to the epidemiology of recurrence, and to facilitate better recurrence prediction through identification of novel risk factors for recurrent VTE.
The study population was derived from one or more of the six surveys (Tromsø 1-6) of the Tromsø Study, with nearly 40.000 participants who were followed from 1994 through 2012. All potential cases of first lifetime and recurrent VTE events during this time-period were recorded. The target population for papers I and II were participants recruited from Tromsø 4 who had suffered a first lifetime VTE in the course of follow-up, whereas the target population for papers III and IV comprised of subjects participating in either of the first six surveys (Tromsø 1-6) who suffered an incident VTE in the period 1994-2012.
First, we found that hospitalization was a major trigger factor for a first VTE, and that the VTE risk was mainly influenced by the length of hospital stay rather than the frequency of hospital admissions in the 90-days prior to VTE. Furthermore, hospitalization was a high-risk situation also in the absence of immobilization, although immobilization contributed substantially to the VTE risk among hospitalized patients.
Secondly, we discovered that the rates of recurrence and mortality after a first VTE remain high, particularly in the following year after a VTE, despite recent advances in the diagnostics and treatment of VTE patients. In paper III, we found that the risk of recurrence among patients with a hospital-related first VTE appeared to be dependent on the reason for hospitalization, although not when the competing risk of death was accounted for. In the final model, patients with a VTE related to hospitalization for medical illness had a high risk of recurrence, similar to that of patients with a non-hospital-related VTE, which may imply a favorable risk-benefit-profile for prolonged treatment. Finally, we identified that d-dimer, measured at first VTE diagnosis, could be a potential biomarker to identify patients at low risk of recurrence, in whom short-term anticoagulant therapy could be sufficient.
Hovedveileder Professor Sigrid Brækkan, IKM, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet.
Biveileder Professor John-Bjarne Hansen, IKM, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet
Professor Paul Alexander Kyrle, Medical University of Vienna, Østerrike
Førsteamanuensis Astrid van Hylckama Vlieg, Leiden University, Nederland
Professor Heidi Tiller, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet – leder av komité
Disputasleder: Førsteamanuensis Knut Fredriksen, IKM, Det helsevitenskapelige fakultet, UiT Norges arktiske universitet
Prøveforelesning over oppgitt emne holdes kl. 10.15, samme sted:
«Venous thromboembolism: studies on the natural course of disease and its implications for the development of novelmanagement strategies”