Gaining Insight Into the Complexity of Pain in Patients With Haemophilia

Joint pain has been reported as a major problem in people with haemophilia (PwH). Therefore, haemophilia in adults seems clinically more related to a musculoskeletal disorder than a bleeding disorder, with many patients reporting a pain intensity exceeding 6/10 on a visual analogue scale. However, although the complexity of joint pain has been studied in chronic joint pain conditions such as low back pain, osteoarthritis or rheumatoid arthritis, until present only very limited research has been done on joint pain within PwH. Therefore, exploring the underlying mechanisms and the functional implications of this intense joint pain is urgently needed. As such, the main aim of the current prospective observational study is to gain more insights in joint pain in PwH enabling us to move towards adequate pain management in PwH.

In this study, adult patients with moderate or severe Haemophilia from the Haemophilia Treatment Centers will be invited to participate in the study. Patients willing to participate will be asked to complete a battery of questionnaires in the week prior to the study. Patients will undergo a comprehensive baseline evaluation after their regular appointment with their treating hematologist.

During the baseline assessment, the structure of ankle and knee joints will be assessed, using respectively magnetic resonance imaging (MRI) and ultrasound evaluation. Besides, patients will be asked to perform some active movements to quantify the physical functions of the lower limb and will undergo an extensive pain assessment.

During one month following baseline assessment, patients will be closely monitored. They will be asked to fill in a diary linked to their usual logbook in which they indicate the minimal and maximal intensity of pain, location of pain, intake of regular or additional (in case of bleeding) clotting factors, intake of analgesics, occurrence and location of assumed bleeding. Patients will be asked to wear an activity tracker to register the number of steps during this month.The short version of the International Physical Activity Questionnaire (IPAQ) will be used to evaluate the self-reported estimation of weekly physical activity.

During the next 11 months, patients will be asked to fill in three online pain-related questionnaires: the Brief Pain Inventory, Brief Illness Perception Questionnaire and the EQ-5D-5L questionnaire once a month.

Eligibility Criteria:
Inclusion Criteria:

* adult (18-65y) patients with moderate (i.e. between 1 and 5 % normal Factor activity) or severe (less than 1% normal Factor activity) Haemophilia A (i.e. Factor VIII deficiency) or B (i.e. Factor IX deficiency)
* Dutch or French speaking
* Patients who provide their haemophilia treatment regimen to be stable (i.e. a regular treatment during the last 6 months, verified by the existing patients' logbook).

Exclusion Criteria:

* Patients suffering from known neuropathies with definite medical causes independent from the haemophilia (e.g. diabetes polyneuropathy)
* Patients with a haemarthrosis in the month preceding study participation will be excluded as well. In case of doubt, ultrasound will be used to check the presence of bleed in the joint.