Occurrence rates of hemophilia in the United States (US) are higher than what was previously reported in a population-based study conducted more than 20 years ago, according to a report published in Haemophilia.

Hemophilia is a complex disease in which routine treatment is expensive and complications can be severe. The exact number of hemophilia cases are unknown and estimates of the size and characteristics of the US hemophilia population are needed for healthcare planning and resource needs assessments.

John Michael Soucie, PhD, of the division of blood disorders at the Centers for Disease Control and Prevention in Atlanta, Georgia, and associates, used the hemophilia treatment center (HTC) network to determine the incidence and prevalence of hemophilia among men in the United States. The researchers obtained de‐identified surveillance data from 2012 to 2018 from all men who visited an HTC. Data included year of birth, race, Hispanic ethnicity, gender, hemophilia type and severity, and residence zip code. Incidence rates over the 20‐year period were calculated using data from a subset of patients born between 1995 and 2014.

From 139 federally supported HTCs in the United States, data was obtained for 21,748 men with hemophilia (76.5% with hemophilia A; 23.5% with hemophilia B). The average age of the cohort was 23.5 years; 75% of men were younger than 35 years. The majority of cases reported at US HTCs were severe (43.6%) followed by mild (29.6%); 81.2% of men were white.

The age-adjusted prevalence for both types of hemophilia was 15.7 cases per 100,000 men (12.0 for hemophilia A and 3.7 for hemophilia B). Disease prevalence was highest among non-Hispanic whites (15.1) compared with non-Hispanic blacks (12.4) and Hispanics of either race (12.4) per 100,000 cases. State-specific hemophilia prevalence ranged from 1.6 per 100,000 in Delaware to 23.3 per 100,000 in Maine.

Based on the 9587 individuals with hemophilia born during the period index, the average hemophilia incidence was 1 case per 4334 live male births. Although the rates were similar for the earlier two 5-year periods, the rates appeared to be lower for hemophilia in the most recent 5-year periods. The researchers calculated that 29,761 to 32,985 men currently living in the United States have hemophilia, and that the majority of these men receive comprehensive care in specialized clinical centers.

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The study had several limitations. First, not all men with hemophilia receive care in the federally supported HTC network covered by the surveillance. Secondly, lower incidences rates observed in the later years may be due to a larger population of primarily mildly affected patients who had not been diagnosed yet. Additionally, incidence rates may be affected by several confounding factors. Lastly, the female population was not characterized for this disorder.

The authors concluded that “longer acting and more effective treatment products as well as successful gene therapy will lead to decreased bleeding and other complications and may require less frequent follow-up care.”

Reference

Soucie JM, Miller CH, Dupervil B, Le B, Buckner TW.  Occurrence rates of haemophilia among males in the United States based on surveillance conducted in specialized haemophilia treatment centres [published online April 24, 2020]. Haemophilia. doi: 10.1111/hae.13998