Risk of venous thromboembolism occurrence among adults with selected autoimmune diseases: A study among a U.S. cohort of commercial insurance enrollees

Objective: This study assessed the risk of venous thromboembolism (VTE) among privately insured adults in the U.S. with one or more of the following autoimmune diseases: autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). Materials and Methods: Using the Truven Health MarketScan(R) Databases, patients 18-64 years of age with a diagnosis of AIHA, ITP, RA, or SLE in 2007 and a sex and age-group matched comparison group of enrollees were followed up through 2010 to identify VTE events. Survival curve and Cox proportional hazards analyses were conducted to assess differences between groups. Results: Among patients with AIHA, ITP, RA, or SLE, or > 1 of these diseases, the risk of at least one VTE event was 19.74, 7.72, 4.90, 9.89, and 13.35 per 1,000 person-years, respectively; among the comparison group, the risk was 1.91 per 1,000 person-years. The adjusted hazard ratios (aHRs) for VTE among patients with AIHA, ITP, RA, or SLE, or > 1 of these diseases (when compared with the comparison group) tended to decline over follow-up time; at 1 year, the aHRs were 6.30 (95% confidence interval [CI]: 4.44-8.94), 2.95 (95% CI: 2.18-4.00), 2.13 (95% CI: 1.89-2.40), 4.68 (95% CI: 4.10-5.33), and 5.11 (95% CI: 4.26-6.14), respectively. Conclusion: Having AIHA, ITP, RA, or SLE, or > 1 of these diseases was associated with an increased likelihood of a VTE event. More research is necessary to develop better understanding of VTE occurrence among people with autoimmune diseases. Published by Elsevier Ltd.