Increased Risk of Blood Clots in People with Rheumatoid Arthritis

People with rheumatoid arthritis may be more likely than people in the general population to develop blood clots.

These results were published in the Journal of the American Medical Association.

Rheumatoid arthritis (RA) affects an estimated 1.3 million adults in the United States. The condition causes pain, swelling, and stiffness of joints, and can also damage bone and cartilage.

Venous thromboembolism (VTE) includes both deep-vein thrombosis (a blood clot in a vein deep inside the body, often in the leg) and pulmonary embolism (a blood clot that breaks loose and travels to the lung). Pulmonary embolism can be a life-threatening condition.

Some research has suggested that inflammation may increase the risk of VTE. Because RA is a condition that is characterized by inflammation, this raises that possibility that people with RA may have an increased risk of VTE.

To explore the risk of VTE among people with RA, researchers in Sweden conducted a study among more than 40,000 people with RA and more than 200,000 people from the general population.

  • During follow-up, VTE was diagnosed in 2.2% of the people with RA and 1.1% of people in the general population.
  • The increased risk of VTE among people with RA became apparent during the first year after RA diagnosis and remained steady for several years after that.
  • Hospitalization increased the risk of VTE in all people (both those with RA and those in the general population). VTE rates during the year following hospitalization were similar in those with and without RA.

These results suggest that people with RA have a higher risk of blood clots than people in the general population. The elevation in risk occurs soon after RA diagnosis but then remains stable over the next decade.

In spite of the overall increased risk among people with RA, short-term rates of VTE after hospitalization appeared to be similar among people with RA and people in the general population.

Reference: Holmqvist ME, Neovius M, Eriksson J et al. Risk of venous thromboembolism in patients with rheumatoid arthritis and association with disease duration and hospitalization. JAMA. 2012;308:1350-1356.