title: Increased risk of venous thrombosis in persons with clinically diagnosed superficial vein thrombosis: results from the MEGA study.
abstract: Superficial vein thrombosis (SVT) is regarded a self-limiting disorder, although the authors of recent studies showed that ultrasonographically diagnosed SVT is a precursor for venous thrombosis. We aimed to determine whether the same holds true for clinically diagnosed SVT and to what extent it is associated with thrombophilia in a population-based case-control study (ie, Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis). We found that a history of clinical SVT was associated with a 6.3-fold (95% confidence interval [CI] 5.0-8.0) increased risk of deep-vein thrombosis and a 3.9-fold (95% CI 3.0-5.1) increased risk of pulmonary embolism. Blood group non-O and factor V Leiden showed a small increase in SVT risk in controls, with odds ratios of 1.3 (95% CI 0.9-2.0) and 1.5 (95% CI 0.7-3.3), respectively. In conclusion, clinically diagnosed SVT was a risk factor for venous thrombosis. Given that thrombophilia was only weakly associated with SVT, it is likely that other factors (varicosis, obesity, stasis) also play a role in its etiology.
authors.affiliation: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Kirsten
authors.initials: K
authors.lastname: van Langevelde
authors.forename: Willem M
authors.initials: WM
authors.lastname: Lijfering
authors.forename: Frits R
authors.initials: FR
authors.lastname: Rosendaal
authors.forename: Suzanne C
authors.initials: SC
authors.lastname: Cannegieter
mesh_terms: D000017:ABO Blood-Group System / Q000235:genetics / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D005165:Factor V / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D012307:Risk Factors; D019851:Thrombophilia / Q000150:complications / Q000453:epidemiology / Q000235:genetics / Q000378:metabolism; D020246:Venous Thrombosis / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics / Q000378:metabolism
chemical_list: D000017:ABO Blood-Group System; C095381:factor V Leiden; D005165:Factor V