The following article features coverage from the 61st American Society of Hematology Annual Meeting and Exposition. Click here to read more of Hematology Advisor’s conference coverage.

Among patients with nonsevere hemophilia A, inhibitor development may not be associated with increased mortality, according to research presented at the 61st American Society of Hematology (ASH) Annual Meeting in Orlando, Florida.

Most research regarding inhibitor development among patients with hemophilia A involves patients with severe disease. As a result, there is limited evidence regarding patients with nonsevere hemophilia A and the clinical effects of inhibitor development, especially given that this issue is linked to severe bleeding complications regardless of disease severity.

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Researchers evaluated data from the ATHNdataset, which contains information from more than 130 hemophilia treatment centers across the United States, to determine patient demographics, inhibitor status, date of death, and primary cause of death in the nonsevere hemophilia A population.

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The researchers calculated mortality as a ratio of total deaths to the number of person-years at risk for mortality throughout the study period, adjusting for patient births and deaths within the study timeframe. Mortality rates were presented as rates per 1000 person-years.

Information from 6606 patients born between 1920 and 2018 was available in the ATHNdataset; observations were made for 56,064 patient-years, and 85.57% (5653) of all included patients had data available through the whole study period.

Among the 6606 patients, 6435 were inhibitor-negative and 171 were inhibitor-positive. Median age for inhibitor development was 13 years. Inhibitor development was linked to 3 deaths, yielding an inhibitor-related mortality rate of 2.40 per 1000 person-years and an inhibitor to no inhibitor mortality risk ratio of 0.98.

The most common cause of death across the study population was malignancy, which was linked to 27 (19.9%) of the 136 deaths observed in the nonsevere hemophilia A population. Median age at death was 63 years.

“In patients with nonsevere hemophilia A, the development of inhibitors occurred at a relatively early age and was not associated with increased mortality,” the authors wrote.

Disclosures: Some authors have declared affiliations with the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


1.     Lim MY, Cheng D, Kempton CL, Key NS. All-cause and inhibitor-related mortality in non-severe hemophilia A patients in the United States. Oral presentation at: 61st ASH Annual Meeting and Exposition; December 7-10, 2019; Orlando, FL. Abstract 902.