Incidence of upper-extremity deep vein thrombosis in western France: a community-based study

Proximal upper-extremity deep vein thrombosis (UEDVT) is defined by thrombosis of the brachial, axillary, or subclavian veins. It also includes extension to the brachiocephalic vein, superior vena cava, and internal jugular vein. UEDVT is usually classified into primary and secondary forms. Primary UEDVT encompasses unprovoked thrombosis and thrombosis associated with thoracic outlet syndrome. Secondary UEDVT is associated with a known risk factor, which is most frequently the presence of a central venous catheter. Unlike lowerextremity deep vein thrombosis, the association between UEDVT and symptomatic pulmonary embolism is not common. The frequency of symptomatic pulmonary embolism associated with a symptomatic UEDVT is not known precisely but is estimated to be between 3% and 12%. To date, estimates of the incidence of UEDVT have only been obtained through the extrapolation of the proportion of UEDVT recorded in registries of highly selected patients with venous thromboembolism. UEDVT may account for 10% of the number of deep vein thromboses of the extremities; however, the current incidence of symptomatic UEDVT may be higher than expected because of the dramatic increase in the use of central venous catheters over the last years. The EPIGETBO study is an epidemiological study that prospectively enrolled all patients living in a well-defined geographic area in western France who were diagnosed in hospitals or in the community with symptomatic venous thromboembolism. The purpose of this analysis of the EPIGETBO data was to determine the incidence of and risk factors for symptomatic UEDVT occurring over a 2-year period. The methods of the EPIGETBO study have already been extensively described. All patients aged 18 years or older living in the Brest District between March 1, 2013 and February 28, 2015 with an objectively documented, symptomatic, proximal deep vein thrombosis of the extremities were prospectively included in the study. Symptomatic UEDVT was defined as the presence of swelling, pain, and/or redness of the upper extremity. UEDVT had to be confirmed by compression ultrasonography or a computed tomography angiogram. UEDVT patients with no symptoms suggestive of pulmonary embolism did not undergo systematic chest imaging. A standardized case report form was filled in for every patient with proven acute venous thromboembolism. All patients or their families were interviewed directly or by telephone in order to collect clinical data, and the charts of admitted patients were reviewed. The patients’ general demographic characteristics, risk factors for venous thromboembolism, clinical signs and symptoms, date and location of venous thromboembolism and place of diagnosis of venous thromboembolism were recorded. Patients were contacted at least twice to ensure the accuracy of the recorded data and modifications in health condition. The database was checked regularly in order to exclude double entries and to review, validate, and adjudicate the diagnoses of venous thromboembolism. Proximal UEDVT was defined as thrombosis of the brachial vein or a more proximal vein. Etiological workup was left at the discretion of physicians in charge of the patients. Clinical characteristics are described by the mean ± standard derivation and by numbers and percentages. Annual incidence rates of UEDVT per 1,000 inhabitants were calculated as the number of UEDVT cases occurring between March 1, 2013 and February 28, 2015, divided by two and by the population of the Brest District, which was 367,911 as per the 2013 census performed by the National Institute for Statistics and Economics Studies (INSEE). The 95% confidence intervals (CI) were estimated based on a Poisson distribution. The study protocol was approved by the Brest University Hospital Ethics Committee. Individual written consent was not required. Between March 1, 2013 and February 28, 2015, 502 inhabitants of the Brest District were diagnosed with a symptomatic proximal deep vein thrombosis of the extremities. Of them, 72 (14.3%) had a symptomatic proximal UEDVT. The mean age of UEDVT patients was 63.2±18.6 years, 33 (45.8%) were men, 48 (66.75) had a central venous catheter, and active cancer was also reported in 48 (66.7%) (Table 1). The central venous catheters were peripherally inserted central catheters (n=20), port-a-cath (n=17) ports, double or triple lumen catheters (n=10), or not specified (n=1). Of the 48 patients with cancer, 34 (70.8%) had had a central venous catheter placed shortly before or at the time of diagnosis of UEDVT. The UEDVT was more proximal in patients with cancer than in those without cancer: 39/48 (81.25%) cases of UEDVT in cancer patients extended to the subclavian vein or internal jugular vein whereas 11/24 (45.8%) cases did so in non-cancer patients (P=0.003). A symptomatic pulmonary embolism was diagnosed concurrently in six of the 72 patients with UEDVT (8.3%). Five out of these six patients (83.3%) had a central venous catheter in place. The proportion of patients with pulmonary embolism was not different between patients with primary and secondary UEDVT (P=0.47). The overall annual incidence rate of UEDVT was 0.098 per 1,000 inhabitants (95% CI: 0.097 to 0.099). The incidence of UEDVT increased with increasing age (Figure 1A): the annual incidence was 0.047 per 1,000 (95% CI: