Venous thromboembolism (VTE) is a major cause of morbidity and mortality in the United States. There is growing evidence that VTE incidence and mortality rates differ among ethnic/racial groups. Specifically, it has been demonstrated previously that blacks with VTE have a higher proportional rate of pulmonary embolism (PE), as well as a higher case fatality rate from PE compared to whites (

Arch Int Med
2003
;
163
(15):
1843
–8
). We therefore compared the location of DVT (proximal vs. distal) in blacks and whites at the time of diagnosis. The null hypothesis was that there is no difference in the location of DVT between white and black patients at the time of diagnosis. We reviewed all lower extremity Doppler ultrasound studies that were positive for acute DVT at our Institution over a 3-year period to create a retrospective case series of 941 patients. Subjects were further classified by self-reported race (black or white), disposition at diagnosis (inpatient or outpatient), and clot location (proximal or distal). Distal DVT was defined as thrombus in one or more deep veins distal to -- but not including -- the popliteal vein. Results were analyzed using Stata version 10. We found that the rate of any proximal (proximal or both proximal and distal) DVT compared with distal only was significantly higher in black patients (OR = 1.4; 95%CI: 1.03, 1.8; P = 0.032), both for 637 inpatients (OR = 1.3; (0.94, 1.9); P = 0.11) and for 304 outpatients (OR = 2.0; (1.01, 3.8); P = 0.048). These differences persisted after controlling for sex and age. We conclude that blacks with acute lower extremity DVT are more likely to present with proximal DVT than whites. These results confirm earlier suggestions that the proportion of proximal lower extremity DVT is higher in blacks, which might account in part for the higher rate of PE (
Arch Int Med
2004
;
164
(12):
1348
–9
). We are further examining the possible causes of this disparity. Possibilities include genetic factors (such as factor V Leiden which is associated with more distal DVT presentation and is rare in blacks), co-morbid conditions (such as diabetes which is more prevalent in blacks), and access to healthcare and diagnostic services, which may lead to more delayed evaluation. Efforts will also be made to determine rates of idiopathic and provoked DVT in these sub-groups.

Topics:
deep vein thrombosis, deep veins, deep venous thrombosis distal, deep venous thrombosis, proximal, diabetes mellitus, diabetes mellitus, type 2, diagnostic services, doppler ultrasound, factor v leiden, genetic aspects

Disclosures: No relevant conflicts of interest to declare.

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2008, The American Society of Hematology
2008
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