Venous thromboembolism 2011-2018 in Stockholm: a demographic study

Venous thromboembolism (VTE) is an important cause of morbidity and mortality in Western countries. The incidence rate of VTE is estimated at 1-2 cases per 1000 annually. This study was a population-based cohort study of previously treatment naïve patients with a first occurrence of venous thromboembolism (VTE), using data from the administrative health data register of the Stockholm Region 2011-2018. Data on anticoagulant treatment was taken from the Swedish Prescribed Drug Register. We also analyzed all VTE events between 2011 and 2018. Altogether 14,849 naïve incident VTE cases were identified. In 2011 the majority of patients with a first episode of VTE were prescribed warfarin versus non-vitamin K antagonist oral anticoagulants (NOACs), 1144 versus 5. In contrast in 2018, the majority of patients were treated with NOACs, 1049 versus 59 treated with warfarin. Treatment with low molecular weight heparin only decreased from 814 to 683 patients. The frequency of all VTE events in the population increased over time from 1.88/1000 to 1.93/1000 (p = 0.072), and PE diagnoses increased from 0.69/1000 to 0.76/1000 (p = 0.003). In conclusion, during 2011-2018 there has been a shift of prescription of warfarin to a clear predominance of NOACs in the treatment of VTE in the Stockholm Region, in line with current recommendations. In the clinical situation, treatment has been simplified as monitoring of warfarin has decreased substantially. PE events increased during the time period in the population even if the increase was rather modest, while all VTE events did not increase significantly.