Rate of Total Joint Replacement Similar in Hemophilia A and B, Study Reports

José Lopes, PhD avatar

by José Lopes, PhD |

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Hemlibra, acquired hemophilia A

Total joint replacement (TJR) is more common in severe hemophilia patients requiring more frequent treatment, according to a population-based study in Taiwan. The findings also revealed that the incidence of TJR does not differ between hemophilia A and B.

The study, “Comparison of Total Joint Replacement Rate Between Patients With Hemophilia A and Patients With Hemophilia B: A Population-Based and Retrospective Cohort Study,” was published in the journal Clinical and Applied Thrombosis/Hemostasis.

Recurrent episodes of joint bleeding — the hallmark manifestation of severe hemophilia — may result in hemophilic arthropathy (disease of the joints) and subsequent progressive joint damage and irreversible deformities.

TJR has been performed in patients with severe hemophilia who do not respond favorably to conservative measures to lessen pain and restore function. This suggests that the rate of TJR in hemophilia A and B may reflect clinical disease severity, the authors wrote.

Specifically, studies in hemophilia A have reported increased joint bleeding and a higher number of surgeries to correct muscle and skeletal complications. These patients have also shown greater risk for joint arthroplasties, a surgical procedure to restore joint function.

However, studies reporting similar risk of joint bleeds or arthroplasty in hemophilia A and B are scarce, which limits evaluation of whether the B type is less severe.

Aiming to address this gap, the team conducted a large-scale study comparing the incidence of TJR (hip, shoulder, knee, elbow and ankle) between 782 men with hemophilia A and 153 with hemophilia B. Age at end of the study was 35.1 years in the hemophilia A group and 31.6 in the hemophilia B group.

Data were collected from 1997 to 2013 from a subdivision of the Taiwanese National Health Insurance Research Database, which provides health insurance coverage for nearly 100% of the 23.5 million Taiwanese.

No patient had inhibitory antibodies against delivered clotting proteins, or factors, which is the major current complication in hemophilia treatment.

Hemophilia classification was determined through the frequency of replacement therapy, not through clotting factor levels. Of note, while factor VIII is reduced or absent in hemophilia A, factor IX levels are affected in hemophilia B.

Patients were subdivided into three groups  — requiring clotting factor concentrates (CFCs) therapy more than two times per year, less than two times per year, or not needing it/only needing it around the time of surgery.

Patients with either hemophilia A or B patients did not significantly differ in the annual use of CFCs. A total of 101 patients did not need replacement therapy during daily life, including 89 with hemophilia A (11.4% of group total) and 12 (7.8%) with hemophilia B.

Also, 84% of hemophilia A patients and 89.5% of those with the B type required therapy over two times per year.

Except 29 hemophilia A patients with HIV, the rate of comorbidities also was not different between the two groups.

Mean age for TJR was 37.2 years. Among TJR-subjected patients, 80 of 83 (96.4%) with hemophilia A and 15 of 16 (93.8%) with hemophilia B were treated with CFCs more than two times per year.

“This finding implied that [hemophilia patients] with TJR had severe type of hemophilia and required more replacement therapy,” the researchers wrote.

The data also showed that a total of 99 (10.6%) patients underwent 142 TJR procedures (116 in hemophilia A patients), all of whom had received on-demand therapy. Incidence of TJR was not statistically different between the two groups (10.6% in A and 10.5% in B). The most common TJR type was knee (72.3% in A, 68.8% in B), followed by hip (20.5% in A, 18.8% in B).

Risk for TJR was not greater in patients with hemophilia A than in those with hemophilia B after adjusting for age, pyogenic arthritis (painful infection of a joint), and HIV infection, as all may affect timing of surgical intervention, the team noted.

Overall, the study “provides evidence that the risk of TJR is not different between patients with [hemophilia A and B],” the scientists wrote.

Among the study’s limitations, they mentioned the lack of satisfactory representation of mild hemophilia, and not having detailed clinical information such as patients’ baseline clotting factor levels.