Venous thromboembolism risk increased with rheumatoid arthritis

Having rheumatoid arthritis tripled the risk for developing deep vein thrombosis and doubled the risk for pulmonary embolism in an analysis of data on 146,190 Taiwan residents.

Investigators identified 29,238 people with new diagnoses of rheumatoid arthritis in 1998-2008 in a national database with health records on Taiwan’s entire population of 23.7 million people. They extended the monitoring period for the study to the end of 2010 and compared the rheumatoid arthritis cohort with 116,952 control patients matched by sex and age in the year of diagnosis.

Expressed in person-years of follow-up, the incidence density of deep vein thrombosis was significantly higher in patients with rheumatoid arthritis (11 per 1,000 person-years), compared with the control group patients (3 per 1,000 person-years). The incidence density of pulmonary thromboembolism also was significantly higher in patients with rheumatoid arthritis compared with controls (4 vs. 2 per 1,000 person-years), Dr. Wei-Sheng Chung and his associates reported Aug. 7 in the Annals of the Rheumatic Diseases.

^{Courtesy Dr. Chia-Hung Kao}

Dr. Wei-Sheng Chung

In all, the data included 193,753 person-years of follow-up in the rheumatoid arthritis group and 792,941 person-years of follow-up in the control group.

After adjusting for age, sex, and comorbidities, the rheumatoid arthritis group had a 3.36-fold higher chance of developing deep vein thrombosis and a 2.07-fold higher risk for developing pulmonary embolism, compared with controls, reported Dr. Chung of Taichung (Taiwan) Hospital and his colleagues (Ann. Rheum. Dis. 2013 Aug. 7 [doi:10.1136/annrheumdis-2013-203380]).

The greatest rise in risk was seen in young adults (50 years or younger) with rheumatoid arthritis, who had a nearly six-fold increased risk for deep vein thrombosis and a tripled risk for pulmonary embolism, compared with controls. The increased risk for deep vein thrombosis was seen mainly in the first 4 years after diagnosis of rheumatoid arthritis, which relied on American College of Rheumatology 1987 criteria that may have identified the disease at a later stage, the investigators suggested. The ACR and the European League Against Rheumatism (EULAR) revised their classification criteria in 2010 to focus on features at earlier stages of the disease.

Patients with rheumatoid arthritis were significantly more likely than controls to have comorbidities, including hypertension, diabetes, hyperlipidemia, heart failure, or lower leg fracture or surgery. The presence of both rheumatoid arthritis and a comorbidity multiplied the risk for thromboembolism, with a six-fold increased risk for deep vein thrombosis and a four-fold increased risk for pulmonary embolism, compared with patients with neither rheumatoid arthritis nor a comorbidity.

"Providing adequate care for patients with rheumatoid arthritis with comorbidities is an important step in preventing further development of deep vein thrombosis and pulmonary embolism. Thus, a multidisciplinary team should guide the assessment, treatment and holistic care of patients with rheumatoid arthritis," Dr. Chung and his associates concluded.

In Taiwan, an estimated 0.1% of the population has rheumatoid arthritis, which is lower than rates of 0.5%-1% in Western countries, they noted. In general, venous thromboembolism leads to death within 30 days in 11%-30% of patients, previous data show.

Two recent population-based cohort studies of patients in Sweden (JAMA 2012;308:1350-6) and in the United Kingdom (Ann. Rheum. Dis. 2013;72:1182-7) reported a doubling in risk for venous thromboembolism in people with rheumatoid arthritis. The differences in increased risk seen in the Taiwan and Western studies may be associated with racial differences, the Taiwanese investigators suggested.

The study cohort was 77% female and had a mean age of 52 years.

The findings are limited by the fact that the Taiwanese database did not include information on smoking, body mass index, physical activity, severity of rheumatoid arthritis, and use of drugs that could affect risk, including hormone replacement therapy, anticonceptive drugs, or glucocorticoids.

Chronic inflammation in patients with rheumatoid arthritis has been associated with prothrombotic factors and endothelial dysfunction in the development of atherothrombosis in prior studies.

Dr. Chung reported having no financial disclosures. The Taiwan government and Taichung Hospital funded the study.

sboschert@frontlinemedcom.com

On Twitter @sherryboschert