Analyses of joint health and influencing factors in different age groups of Chinese children with haemophilia

Haemophilia is the most common hereditary haemorrhagic disorder. The worldwide incidence of haemophilia A in men is 1 per 10 000 population [1]. Spontaneous haemorrhage into joints, muscles and organs, or haemorrhage due to minor trauma, are the main manifestations. Joint haemorrhage is the most common, accounting for 70–80% of all cases of haemorrhage [2]. Full-dose prophylaxis is very effective at minimizing joint damage but is expensive. If left untreated, disability occurs early. Soucie et al. [3] reported that full range of motion is affected in approximately 85% of patients with severe haemophilia. Currently, prophylactic treatment is rarely available to haemophilia patients in ‘developing’ countries, resulting in repeated polyarticular haemorrhage in many children. Recurrent haemorrhage into joints initiates a sequence of events that lead to progressive damage to joints: pain, continued swelling, crepitus, reduced range of motion, muscle atrophy around the joint and decreased proprioception. Nearly 50% of Chinese patients with haemophilia are aged 0– 14 years and have a high incidence of haemorrhage and joint dysfunction according to the data from Chinese management center of the national hemophilia information. This study provides clinical evidence to improve the joint health of children by investigating joint health and influencing factors. The study protocol was approved by the Medical Ethics Committee of Beijing Union Medical College Hospital (Beijing, China). This study was conducted in accordance with the Helsinki Declaration. Sixty boys with haemophilia formed the study cohort. The exclusion criteria were as follows: patients with severe traumatic haemorrhage, joint abnormalities caused by other congenital hereditary diseases or developmental abnormalities, severe disease of the heart, liver, brain, lungs, kidneys, infectious disease and patients who refused to comply with assessment of joint health. Approximately 95% of the study cohort had haemophilia A: five patients had severe haemophilia (factor VIII <1%), 52 had moderate haemophilia (factor VIII 1–5%) and three had mild haemophilia (factor VIII 5–40%). The mean age at evaluation was 11.1 years (range: 4–18 years). Two patients had a history of high titre inhibitors against factor VIII. The age of the first haemorrhage was 0–60 months (average: 16 15.83 months). The frequency of haemorrhage in the past 3 months was 0–16 times (average: 4.22 3.68 times). The number of patients with a history of muscle haemorrhage was 46. Twenty-five patients received prophylaxis on an irregular basis, and 35 received on-demand treatment. An average dose of replacement treatment in the past 3 months was reported as <10 U/kg in 28 boys, and 10 U/kg for 32 boys. A course of prophylaxis of <3 months was documented for two boys, 3–12 months for 17 boys and >12 months for six boys. Prophylaxis was given once a week in 13 boys and twice a week in 12 boys. The Haemophilia Joint Health Score (HJHS) was developed by the Physiotherapy Subcommittee of the International Prophylaxis Study Group for evaluation of joint function in paediatric patients with haemophilia. We used HJHS v2.1 to evaluate the joint function in children with haemophilia in this study. HJHS was used for the assessment of the elbows, knees and ankles for the following parameters: loss of range of motion, swelling, duration of swelling, muscle atrophy, axial alignment, crepitus upon motion, joint pain, muscle strength around joints and global gait. It is a useful tool for the identification and tracking of changes in joint health with respect to therapy or disease progression. Its reliability is excellent, with an inter-observer coefficient of 0.83 and a test–retest value of 0.89 in one study [4]. Although developed for assessment of young children, Fischer et al. [5] showed that the HJHS can also be used for the evaluation of teenagers and young adults with limited haemophilic arthropathy. HJHS is more sensitive for the Correspondence: Lixia Chen, Department of Physical Medicine and Rehabilitation, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Beijing 100730, China. Tel.: +86 13691060078; fax: 86-10-69157335; e-mail: clx727@126.com