The incidence and prevalence of Evans syndrome, a rare disease characterized by the co-occurrence of immune thrombocytopenia and autoimmune hemolytic anemia, appears to have increased over time, according to research published in the American Journal of Hematology.

In this retrospective study, investigators used health registries to identify 242 patients with Evans syndrome in Denmark between 1977 and 2017. They compared survival and mortality of this cohort with 3 age- and sex-matched cohorts: patients with only immune thrombocytopenia, patients with only autoimmune hemolytic anemia, and individuals from the general population.

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Patients with Evans syndrome were diagnosed at a mean age of 58.5 years (95% CI, 55.9-61.0) and 51.2% of patients were female. Secondary Evans syndrome, defined as co-occurring with another hematologic malignancy, rheumatic disorder, or other specific disease, occurred in 27.3% of patients. During the 40-year study period, incidence was 0.97 (95% CI, 0.40-1.07) per million person years between 1980 and 1993, 0.68 (95% CI, 0.40-1.07) per million person years between 1994 and 1999, and 1.84 (95% CI, 1.55-2.16) per million person years between 2000 and 2016. Between 1980 and 2016, the 1-year period prevalence increased from 3.30 (95% CI, 1.80-5.60) to 21.30 (95% CI, 17.40-25.80) per million persons.

Median survival was 10.9 years (95% CI, 5.8-15.0) for patients with primary Evans syndrome, 1.7 years (95% CI, 1.1-3.4) for patients with secondary Evans syndrome, and 7.2 years (95% CI, 3.9-11.2) for all patients. Patients with Evans syndrome had higher mortality compared with patients who had either only immune thrombocytopenia or only autoimmune hemolytic anemia, and patients with secondary Evans syndrome had higher mortality than all other cohorts. The Evans syndrome cohort demonstrated significantly increased risk for death due to bleeding (subdistribution hazard ratio [subHR], 4.1; 95% CI, 1.8-9.5), hematologic cancer (subHR, 23.9; 95% CI, 12.9-44.4), and other causes (subHR, 1.7; 95% CI, 1.1-2.6) compared with the general population cohort.

The authors concluded that both incidence and prevalence of the syndrome have increased over time. Given that both primary and secondary Evans syndrome confer a poor prognosis, “suspicion of Evans syndrome should prompt vigilant clinical follow-up.”

Reference

1.     Hansen DL, Möller S, Andersen K, Gaist D, Frederiksen H. Evans syndrome in adults – incidence, prevalence, and survival in a nationwide cohort [published online July 10, 2019]. Am J Hematol. doi:10.1002/ajh.25574