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Respiratory infection increases DVT risk

By Christian Duffin

Patients who have had recent respiratory infection are at significantly increased risk of venous thromboembolisms, according to a UK study.

Researchers identified all patients aged 18 and over with a first-time diagnosis of deep-vein thrombosis or pulmonary embolism from the IMS database, a primary care database of 3.5 million patients registered at 670 practices, together with single-matched controls.

From a sample of 11,557, 457 patients with deep vein thrombosis also had a respiratory infection in the year before the index date, compared with only 262 DVT cases among patients who had not had an infection.

This represented a 2.6-fold increased risk, which persisted for a year. There was also a 2.5-fold increased risk of pulmonary embolism in the three months following an infection.

Study leader Dr Tim Clayton, a senior lecturer in epidemiology and public health at the London School of Hygiene and Tropical Medicine, said: ‘It is by no means standard practice in the UK that patients with an acute respiratory infection should receive anti-thrombotic prophylaxis, but the possibility that they might benefit is one of the important questions raised by our study, which can only be settled by a randomized controlled trial.'

Int J Epidemiol 2011, published online February 2011