The Relative Health-Related Quality of Life Burden of Severe Hemophilia A and the Impact of Target Joint Development.
Authors: Epstein Joshua D , Luu Huong , Yarlas Aaron S , Hammond Geoffrey 
Published: October 2019

Abstract
Abstract 1404
Poster Board I-426

Objectives:
The primary objective of this study was to compare the Health-Related Quality of Life (HRQOL) burden of severe hemophilia A patients relative to a healthy sample of people, a general sample of the population, and to patients with other burdensome chronic conditions. The secondary objective was to determine the HRQOL impact of having at least one target joint.

Methods:
All adult patients with severe hemophilia A who were enrolled in the Antihemophilic Factor (Recombinant), Plasma/Albumin-Free Method (Advate) Post-Authorization Safety Surveillance (PASS) study and completed the SF-36v2 at their baseline assessment were selected for this research. Analysis of variance was used to assess the relative HRQOL burden of these hemophilia A patients as compared to a healthy US population sample, a normal US population sample and patients reporting either chronic back pain, rheumatoid arthritis, or cancer. This comparison data was collected from the 1998 US National Survey of Functional Health Status. These comparisons groups were adjusted to the age and sex distribution of the severe hemophilia A sample using OLS regression models, with each SF-36v2 scale/summary score as a dependent variable. Finally, multivariate analysis of covariance (controlling for age) tested the impact of target joint absence (TJ-) or presence (TJ+) on SF-36v2 scores.

Results:
141 adult patients (ages 18–78; median age=35) were identified. These severe hemophilia A patients scored worse than the US healthy population and US general population on all four physical domain scales and lower than chronic back pain patients on three out of the four physical domain scales (all p<0.01). The mean physical component summary (PCS) score was 41.6 for these hemophilia A patients and 54.3, 51.3, and 47.4 for the US healthy population, US general population and chronic back pain patients (all p<0.01); all exceeding this measure's established minimal important difference (MID) of 3 points. Hemophilia A patients reported no differences in physical HRQOL on the SF-36v2 when compared to patients with rheumatoid arthritis and cancer (p>0.05). Interestingly, hemophilia A patients reported significantly a higher score on both the vitality domain and mental component summary (MCS) score when compared to all patient groups except the US healthy population (all p<0.01). In addition, the difference on the MCS between hemophilia A patients and patients with chronic back pain, rheumatoid arthritis, and cancer were larger than the MID (50.6 vs 45.2, 44.4, and 44.7, respectively). Forty-six (32.6%) severe hemophilia A patients enrolled in the PASS study did not have a target joint. Hemophilia A patients without target joints showed significantly better HRQOL than patients with at least one target joint on the physical functioning scale (p<0.05), the general health scale (p<0.01) and the PCS score (p<0.01). The difference between the mean PCS score exceeded the MID (44.8/40.1 for TJ-/TJ+ groups, p<0.01). There were no differences between hemophilia A patients with and without target joints for any of the mental scales or the MCS score (p>0.05).

Conclusion:
These comparisons demonstrate that severe hemophilia A patients have significantly significant and clinically meaningful lower physical HRQOL compared to the general public and people suffering from chronic back pain. The physical burden that these severe hemophilia A patients reported was similar to those who were living with rheumatoid arthritis or cancer. If target joints are prevented, hemophilia A patients may be able to experience significantly better physical HRQOL than if they developed a target joint. Finally, this research demonstrated that hemophilia A patients were unique compared to the other three chronic conditions studied, because hemophilia A patients reported significantly higher mental HRQOL than patients with chronic back pain, rheumatoid arthritis and cancer.

Disclosures:
Epstein: Baxter BioScience: Employment. Luu: Baxter BioScience: Employment. Yarlas: Baxter BioScience: Consultancy. Hammond: Baxter BioScience: Consultancy.