Venous Thrombosis in Wegener Granulomatosis

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The summary below is from the full report titled "Brief Communication: High Incidence of Venous Thrombotic Events among Patients with Wegener Granulomatosis: The Wegener's Clinical Occurrence of Thrombosis (WeCLOT) Study." It is in the 19 April 2005 issue of Annals of Internal Medicine (volume 142, pages 620-626). The authors are P.A. Merkel, G.H. Lo, J.T. Holbrook, A.K. Tibbs, N.B. Allen, J.C. Davis Jr., G.S. Hoffman, W.J. McCune, E.W. St. Clair, U. Specks, R. Spiera, M. Petri, and J.H. Stone, for The Wegener's Granulomatosis Etanercept Trial Research Group.

What is the problem and what is known about it so far?

Wegener granulomatosis is an uncommon disease in which the blood vessels are inflamed (vasculitis). The inflammation of the vessels limits blood flow to body organs. Wegener granulomatosis mainly affects the respiratory tract and the kidneys. Symptoms are often vague and may include cold symptoms, such as runny nose, sinus pain, bloody discharge from the nose, cough, shortness of breath, joint pains, rashes, weakness, or tiredness. Some patients with Wegener granulomatosis also get blood clots in their veins (venous thromboembolism or VTE). These clots can cause serious and even fatal complications. Researchers do not know how often VTEs occur in patients with Wegener granulomatosis.

Why did the researchers do this particular study?

To find out how often patients with Wegener granulomatosis have VTEs.

Who was studied?

180 adults with Wegener granulomatosis who were enrolled in a multicenter drug treatment trial; 167 of them had no history of VTEs.

How was the study done?

The researchers followed the patients every 3 months from June 2000 through December 2002. They assessed symptoms and signs of Wegener granulomatosis and adverse events, such as VTEs. They used any of several tests to confirm suspected VTEs, including lung scanning, ultrasonography, and dye tests of the vessels in the legs or lungs. The researchers summed the amount of time that patients were followed by using a measure called person-years. With this measure, 1 person followed for 2 years contributes 2 person-years, while 10 people followed for 6 months contribute 5 person-years. The researchers then estimated the incidence of VTEs per person-year of follow-up.

What did the researchers find?

16 VTEs occurred in patients with no history of VTEs. The incidence of VTEs was 7 per 100 person-years.

What were the limitations of the study?

The researchers tested for VTE only if patients had symptoms or physical signs that suggested VTE. Some VTEs may have been missed.

What are the implications of the study?

Patients with Wegener granulomatosis have a high incidence of VTE. Their incidence of 7 VTEs per 100 person-years is much higher than that in the general population (about 0.3 per 100 person-years) and is also higher than that in patients with systemic lupus erythematosus (about 1 per 100 person-years).