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

INTRODUCTION: The Haemophilia Joint Health Score (HJHS) is a validated physical exam measure of haemophilic arthropathy, used clinically to determine treatment adequacy. Higher scores are worse; however, there is no consensus on a clinically significant score. AIM: To establish HJHS reference ranges based on age and haemophilia type and severity, relative to prophylaxis, inhibitor status, annualised bleeding rate and body mass index. METHODS: This is a cross-sectional analysis of HJHS exams performed between 2012 and 2021 by the University of Colorado Hemophilia and Thrombosis Center in persons with Factor VIII or IX <50%. For each haemophilia type, severity and age group, reference ranges were defined using interquartile ranges, and the percentage of joints with scores overlapping healthy controls were calculated. Univariate and multivariable linear regression determined the influence of modifiers on total HJHS. The association between total HJHS and pain on exam was also evaluated. RESULTS: Initial analysis of all participants showed female and male HJHS values to be statistically different for reasons requiring further investigation; subsequent analyses were limited to males. Multivariable linear regression derived from data on 385 males showed that for each 1-year age increase, total HJHS was 0.5 points higher. Total HJHS were 3.9 points higher in Haemophilia A than Haemophilia B. Ranked haemophilia severity (severe > moderate > mild) incurred 2.4 point increases in total HJHS. Pain was present in 76% of joints with individual joint scores >10. CONCLUSION: This study quantifies current differences in total HJHS relative to haemophilia type, severity, age and treatment in males.