Prevalence of Haemarthrosis and Clinical Impact on The Musculoskeletal System in People With Haemophilia in The United Kingdom; Evaluation of UK National Haemophilia Database and Haemtrack Patient Reported Data.

Introduction; Severe haemophilia is a rare x-linked recessive genetic disorder characterised by bleeding into soft tissue and joints. Haemarthrosis is the most common bleeding manifestation in haemophilia, leading to haemarthropathy. The ankle joint has been reported as the most common site of bleeding, but it is unclear whether the ankle is most affected in terms of joint health status. Aims; To determine the prevalence of joint bleeding and musculoskeletal health status at an individual joint level of children and adults with severe haemophilia A and B without a current inhibitor.Methods; Application was made to the National Haemophilia Database (NHD) with a request for the following; Haemtrack patient reported treatment record and Haemophilia Joint Health Scores (HJHS) in children (<18y) and adults (≥18y) with severe haemophilia A (HA) and B (HB) (FVIII/FIX, <0.01 iu/ml) without a current inhibitor. Data were collated and reported for 1st January to 31st December 2018.Results; 2238 cases were identified, of which 273 were Haemtrack compliant with contemporaneous HJHS. The median (IQR) age of children was 10 (6-13) and adults 40 (29-50) years. Haemarthrosis prevalence in HA/HB children was 33% and 47%, respectively and 60% and 42%, respectively, in adults. The most common haemarthrosis site in children was the knee in HA and ankle in HB. In adults, the incidence of haemarthrosis at the ankles and elbows was equal. Median (IQR) total HJHS in HA/HB children were 0 (0;0). In adults with HA/HB, HJHS were 18 (6; 31) and 11 (5; 24), respectively. In adults with HA/HB, mean (SD) ankle HJHS of 3.8 (4.1) and median 4.0 (0.0; 8.0) were higher than the knee (mean 2.9 (4.1) and median 1.0 (0.0; 5.0) and elbow (mean 3.3 (4.1) and median 1.0 (0.0; 7.0) joints.Conclusion; During 2018, NHD prevalence data of haemarthrosis indicate only two-thirds of children and one-third of adults from a UK cohort compliant with prophylaxis were bleed free. HJHS of zero in children suggests joint health status is either unaffected during childhood or undetected by HJHS. In adults, higher HJHS are reported for the ankles indicating worse joint health.