People with autoimmune disease such as lupus and rheumatoid arthritis (RA) are more likely to get dangerous blood clots during hospital stays. In fact, one 2014 Arthritis Research & Therapy meta-analysis of 25 studies found that people with inflammatory rheumatic diseases were three times more likely to experience venous thromboembolisms (VTEs, or blood clots in the veins) than the general population.
Lupus patients are four times more likely than people without an autoimmune disease to develop blood clots when hospitalized. And RA patients are one-and-a-half times more likely to develop blood clots during a hospital stay. According to a 2011 study from researchers in the United Kingdom, anyone with an immune-related disorder faces some sort of increased risk.
“For some diseases, such as RA, the risk increase is fairly small in epidemiological terms, but for others the effect is much greater,” says Sreeram Ramagopalan, PhD, a study author from the University of Oxford in the United Kingdom. “These blood clots are potentially fatal and this data should be taken into account when patients with autoimmune disease are admitted to the hospital so that preventative measures can be taken.”
Ramagopalan says it was previously known that patients with some autoimmune diseases, like Crohn’s disease and type 1 diabetes, had an increased risk of blood clots. But he says their study, published in the journal BMC Medicine, showed for the first time that patients with many other autoimmune diseases have this increased risk as well.
What’s the Connection?
Researchers say it’s possible that inflammation is causing this increased risk. “It needs to be studied as to exactly why patients with autoimmune disease are at an increased risk, but there is good evidence to suggest that autoimmune processes may lead to clots,” Ramagopalan says.
“Inflammation is associated with changes in the blood that tip the hemostatic balance toward clot formation. These findings are consistent with previous studies demonstrating an increased risk of blood clots in patients with inflammatory bowel disease and infections,” says Michael Streiff, MD, medical director of the Anticoagulation Management Service and Outpatient Clinics at Johns Hopkins Medical Institutions in Baltimore. “It makes sense biologically that these patients would be at higher risk for blood clots.”
Given their findings, study researchers suggest patients at increased risk of blood clots consider asking for and taking anti-clotting drugs while they’re in the hospital. “It has been estimated that there are thousands of deaths in hospitals due to VTE, which could have potentially been prevented,” Ramagopalan says.
Dr. Streiff agrees. “[Patients] need to say, ‘I hear I’m at higher risk because I have RA and am in the hospital,’ and make sure their doctors are giving them that medicine,” Dr. Streiff says. He says patients may need to continue taking the medication when they check out too, particularly if they are in the hospital for only a few days.
“Often times we just give those [medications] for the duration of the hospitalization, but the risk of blood clots often extends beyond a few-day hospital stay, as many patients are still recovering from an illness after they return home. Perhaps some rheumatologic conditions, such as lupus, warrant continued treatment with anti-clotting drugs after discharge,” Dr. Streiff explains. “Further studies of the risk of clotting posed by these illnesses and the preventive benefits of anti-clotting medications are warranted.”
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