Haemophilia Joint Health Score Ranges Across the Lifespan: Variation by Haemophilia Type and Severity

Area of Science:

• Orthopedics
• Hematology
• Rheumatology

Background:

• The Haemophilia Joint Health Score (HJHS) is a key clinical tool for assessing joint health in individuals with haemophilia.
• Establishing reference ranges for HJHS is crucial for interpreting treatment adequacy and disease progression.
• Current understanding lacks defined clinically significant HJHS score thresholds.

Purpose of the Study:

• To determine age- and haemophilia type/severity-specific reference ranges for the HJHS.
• To analyze the influence of prophylaxis, inhibitor status, bleeding rate, and BMI on HJHS.
• To correlate HJHS with pain experienced by patients.

Main Methods:

• Cross-sectional analysis of HJHS data from 2012-2021 at a Hemophilia and Thrombosis Center.
• Inclusion criteria: individuals with Factor VIII or IX <50%.
• Statistical analysis included interquartile range for reference ranges, univariate/multivariable regression, and pain association evaluation.

Main Results:

• Analysis was limited to males due to initial observed differences in female/male scores.
• Multivariable regression in 385 males indicated HJHS increases with age (0.5 points/year), is higher in Haemophilia A (3.9 points), and increases with severity (2.4 points).
• Pain was reported in 76% of joints with HJHS scores exceeding 10.

Conclusions:

• This study provides quantified HJHS differences based on age, haemophilia type, and severity in males.
• Findings aid in better understanding HJHS interpretation in clinical practice.
• Further investigation is needed regarding observed sex-based differences in HJHS.