%0 Journal Article
%T Influenza infection and risk of acute pulmonary embolism
%A Matthijs van Wissen
%A Tymen T Keller
%A Brechje Ronkes
%A Victor EA Gerdes
%A Hans L Zaaijer
%A Eric CM van Gorp
%A Dees PM Brandjes
%A Marcel Levi
%A Harry R B¨¹ller
%J Thrombosis Journal
%D 2007
%I BioMed Central
%R 10.1186/1477-9560-5-16
%X We conducted a nested case control study in a large cohort of patients with a clinical suspicion of having pulmonary embolism. Blood samples were collected to investigate the presence of influenza A and B by complement fixation assay (CFA). We compared case patients, in whom pulmonary embolism was proven (n = 102), to controls, in whom pulmonary embolism was excluded (n = 395). Furthermore, we compared symptoms of influenza-like illness in both patient groups 2 weeks prior to inclusion in the study, using the influenza-like illness (ILI) score, which is based on a questionnaire. We calculated the risk of pulmonary embolism associated with influenza infection.The percentage of patients with influenza A was higher in the control group compared to the case group (4.3% versus 1.0%, respectively, odds ratio 0.22; 95% CI: 0.03¨C1.72). Influenza B was not detectable in any of the cases and was found in 3 of the 395 controls (0.8%). The ILI score was positive in 24% of the cases and 25% in the control persons (odds ratio 1.16, 95% CI: 0.67¨C2.01). We did not observe an association between the ILI score and proven influenza infection.In this clinical study, influenza infection was not associated with an increased risk of acute pulmonary embolism. The ILI score is non-specific in this clinical setting.Deep vein thrombosis and pulmonary embolism, collectively known as venous thromboembolism (VTE), have an annual incidence of approximately 2¨C3 per 1000 people [1]. Many risk factors of venous thromboembolism have been well established, including genetic predisposition, immobilization, surgery, pregnancy, oral contraceptives and malignancies. However, there are patients who develop venous thromboembolism in the absence of one of these risk factors. There is growing evidence that acute infections are associated with an increased risk of developing a venous thromboembolic event.Emmerich and others found an association between positive antibody titers for Chlamydia pneumoniae and veno
%U http://www.thrombosisjournal.com/content/5/1/16