Effect of introducing biologics to patients with rheumatoid arthritis on the risk of venous thromboembolism: a nationwide cohort study

In the United States, 100,000-300,000 patients die from venous thromboembolism (VTE) each year, with more than 500,000 people related hospitalizations. While in Europe, 500,000 people die from VTE each year. Patients with rheumatoid arthritis are at increased risk of VTE. The use of biologics in patients with rheumatoid arthritis may be associated with an increased risk of VTE. We identified all patients who had been newly approved for Catastrophic Illness Card of rheumatoid arthritis extracted the claims data from the National Health Insurance research database and Registry for Catastrophic Illness Patient Database from 2003 to 2016. VTE was defined as the presence of inpatient VTE diagnostic codes (including DVT or PE) according to the discharge diagnosis protocol. An analysis of VTE variables indicated that the incidence of VTE in the biologic group (14.33/10,000 person-years) was higher than that in the conventional drug group (12.61/10,000 person-years). As assessed by the Cox proportional hazards model, the relative HR for VTE in the biologic group (HR: 1.11; 95% CI 0.79-1.55) versus that in the conventional drug group did not reach a significant difference. In conclusion, this study found no significant differences in risk were observed between the use of conventional DMARDs and biologics.