Most patients with hemophilia, regardless of age, are likely to have low bone mass, with the exception of patients with moderate hemophilia B (HB), according to research published in Haemophilia.

Hemophilia A (HA) and HB are, respectively, caused by X-linked recessive inherited factor VIII (FVIII) and factor IX (FIX) deficiencies. Disease severity is determined by plasma levels of FVIII or FIX activity, with lower factor levels vs the normal population classified as more severe.

Patients with mild or moderate HA or HB tend to have bleeding events after traumas or invasive procedures, while patients with severe disease may develop musculoskeletal bleeding and intramuscular hemorrhages, which can lead to chronic arthropathy. Regardless of age, patients with HA or HB tend to have low bone mass and impaired bone strength, which is linked with a variety of related problems and may be related to low 25-hydroxyvitamin D (25[OH]D) concentrations.

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Differences in disease severity between HA and HB are not established, though some evidence suggests that patients with HB may have lower bleeding frequency and better overall clinical outcomes. For this study, researchers aimed to establish any association between bone mass density, 25(OH)D concentration, and hemophilia type and severity.

Data from 78 patients younger than 50 years and 33 patients older than 50 years were evaluated. All patients had severe or moderate HA or HB. Bone mass density was determined by X-ray absorptiometry and evaluated against measurements including annual bleeding rates (ABRs), World Federation of Hemophilia (WFH) orthopedic joint scale score, and 25(OH)D concentrations.

Low 25(OH)D concentrations were common across evaluated patients. In patients younger than 50 years, those with HA had an average 25(OH)D concentration of 20.38 ng/mL, compared with 21.27 in those with HB. In patients older than 50 years, those with HA had an average 25(OH)D concentration of 21.85 ng/mL, compared with 20.33 in those with HB. A normal range, by contrast, is 30 ng/mL to 100 ng/mL.

In patients younger than 50 years, low femoral-neck bone mass density was significantly more common among patients with HA (P =.02). Across age groups, ABRs and WFH scores were less severe in patients with HB.

Among patients who were older than 50 years, low bone mass density rates did not significantly vary between HA and HB.

“In conclusion, low bone mass has been confirmed as a frequent comorbidity in [hemophilic] patients of all ages,” the authors wrote. “The high prevalence of hypovitaminosis D, independently from the age, type and severity of [hemophilia] and virological status, suggests to systematically evaluate serum 25(OH)D concentrations for proper supplementation.”

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


Linari S, Melchiorre D, Pieri L, et al. Low bone mass and hypovitaminosis D in haemophilia: a single-centre study in patients with severe and moderate haemophilia A and B. Haemophilia. Published online August 25, 2020. doi:10.1111/hae.14127