Multidimensional Assessment of Chronic Pain in Severe Haemophilia A

Chronic residual pain and its functional interference will be assessed using the Spanish version of the Brief Pain Inventory-Short Form (BPI-SF). This multidimensional self-administered questionnaire explores pain intensity using four items: maximum, minimum, average and current pain, on a scale of 0-10. The degree of interference of pain in daily life is assessed using seven items: mood, activity, work, relationships, sleep, enjoyment of life, and walking, on a scale of 0-10. An average score is calculated for each dimension (intensity and interference). This instrument has shown excellent reliability and validity

Catastrophising will be assessed using the Spanish version of the Pain Catastrophising Scale (PCS). This self-reported questionnaire consists of 13 items measuring three cognitive dimensions related to pain: rumination, magnification and hopelessness. Each item is scored on a Likert scale from 0 ('never') to 4 ('always'), and the total score ranges from 0 to 52. Higher scores indicate higher levels of catastrophising. This tool has shown excellent internal consistency and test-retest reliability. This scale can predict pain intensity and emotional response in clinical and experimental contexts.

Perceived self-efficacy for managing chronic pain will be assessed using the Pain Self-Efficacy Questionnaire (PSEQ). This instrument measures the degree to which a person with chronic pain trusts their ability to perform daily activities despite pain. It consists of 10 items, each scored on a 7-point Likert scale ranging from 0 ('not at all confident') to 6 ('completely confident'). The total score ranges from 0 to 60, with higher values indicating greater self-efficacy. The Spanish version of the PSEQ has shown excellent internal consistency and test-retest reliability.

Body image perception will be assessed using the Spanish version of the Body Image Scale (BIS). This instrument, designed for patients after cancer treatment, consists of 10 self-administered items that assess body image distress resulting from this treatment. It uses a 4-point Likert scale (0 = 'not at all' to 3 = 'very much'). The total score ranges from 0 to 30, with higher values indicating greater impairment. The adaptation to Spanish showed excellent internal consistency.

The sociodemographic variable age will be assessed by calculating the age (in months) from the date of birth to the date of assessment.

The sociodemographic variable educational level will be assessed using closed-ended questions (primary education/secondary education/university education/postgraduate education).

The clinical variable 'time with prophylactic treatment with bispecific monoclonal antibodies' will be calculated in months (time between the start of treatment with this therapeutic option and the date of evaluation).

The clinical variable number of previous bleeds in the last 12 months will be calculated based on the number of clinical haemarthrosis. These must meet a series of criteria to be determined as clinical haemarthrosis: inflammation, restricted range of motion, severe pain, functional impairment and the requirement of at least one dose of clotting factor concentrate as rescue treatment.

The anthropometric variable body mass index will be calculated using the formula Weight/Height2. To do this, both data will be requested from patients at the time of evaluation.