Demographic characteristics, thromboembolism risk, and treatment patterns for patients with cold agglutinin disease in Japan.

Cold agglutinin disease (CAD) is a rare, complement-mediated autoimmune hemolytic anemia. Patients with CAD in the United States and Europe have an increased incidence of thromboembolism (TE), but comparable information for patients in other regions is lacking. Thus, we examined TE risk for patients with CAD in Japan. Patients with CAD (at least three claims with a CAD diagnosis; Japanese Disease Code 2830009) and non-CAD controls were retrospectively identified (2008-2017) from a large hospital-based administrative claims dataset in Japan. Cohorts were compared using conditional logistic regression. We identified 344 patients with CAD (53.2% female; mean age: 66.8 years) and 3440 matched controls. Patients with CAD had higher TE rates than controls (34.9% vs. 17.9%; P < 0.0001). Both arterial and venous TEs were increased in the CAD group when compared with the control group (25.0% vs. 4.6% and 8.4% vs. 4.0%, respectively; both P < 0.0001). Most arterial TEs in the CAD cohort (87.2%) were myocardial infarctions. The overall odds ratio for TE development in CAD was 2.81 (95% confidence interval 2.18-3.61). CAD in Japan is characterized by an increased risk of TE. The rate of arterial TEs was particularly high in this patient population.