Cold agglutinin disease (CAD) patients have an increased risk of developing blood clots compared to the general population, a retrospective Danish study shows.
The findings of the study, “Occurrence, thromboembolic risk, and mortality in Danish patients with cold agglutinin disease” were published recently in the journal Blood Advances.
In CAD, antibodies (known as autoantibodies) attack and destroy red blood cells when the temperature is low. Traditionally, the disease is thought to be a chronic disease without significant risks.
However, a recent American retrospective study reported a correlation between CAD and an increased risk of thromboembolic events — blood clots that block blood circulation, which can be life-threatening.
No studies have compared patients with CAD to the general population for the risk of blood clot formation, making it hard to determine the associated risks and outcomes.
In this retrospective population-based survival study, researchers assessed the risk of mortality and the frequency of thromboembolic events in Danish CAD patients compared with the general population.
They analyzed data from the Danish National Patient Registry collected from 1999 to 2013. The analysis included 72 patients with CAD and 720 individuals from the general population. The two groups were matched for age, sex, and region of residence.
The analysis revealed that the risk of thromboembolic events was higher in CAD patients compared to the controls. The risk for blood clots assessed at after one, three, and five years following diagnosis was always higher in CAD patients — 7.2%, 9.0% and 11.5%, respectively — compared to controls (1.9%, 5.3% and 7.8%). Furthermore, compared with controls, the overall rate of thromboembolic events was 65% higher in CAD patients.
Patients also had an increased risk of mortality compared to the general population, which was detected early on. In fact, the highest mortality rates occurred during the first five years of the disease. One year after diagnosis, CAD patients had an 83% chance of surviving compared to 97% for individuals from the general population, dropping to 61% after five years (individuals from the general population had an 82% survival chance).
Overall, CAD patients had a 2.3 times greater mortality risk compared to the general population during the first five years after diagnosis.
“This is contrary to the traditional belief that as a chronic disease, complications may occur later,” researchers wrote. “One possible explanation for the early risk of death may be the lack of early therapeutic interventions used in these patients.”
Overall, “the results of this population-level comparison study support the increased risk of TEs [thromboembolic events] described in recent reports, and we found that patients with CAD also have increased mortality.
These findings highlight the need for CAD patients to be “carefully monitored, and potential clinical complications should be evaluated promptly,” the study authors concluded.