A new measure to assess pain in people with haemophilia: The Multidimensional Haemophilia Pain Questionnaire (MHPQ).

People with haemophilia (PWH) experience acute pain during joint bleeds and might develop chronic pain due to joint degeneration. However, there is a lack of standardized measures to comprehensively assess pain in PWH. This study aimed to develop a multidimensional questionnaire for haemophilia-related pain, the Multidimensional Haemophilia Pain Questionnaire (MHPQ), and to present initial validation data among adults.The questionnaire distinguishes between acute/chronic pain and queries about pain locations, duration, frequency, triggering factors, intensity, interference, strategies, specialists for pain management and satisfaction with treatment. An initial version was tested with 16 patients to ensure item comprehensibility and face validity. The final version was answered by 104 adults, with 82 (78.8%) reporting haemophilia-related pain in the previous year (mean age = 43.17; SD = 13.00). The non-response analysis revealed good item acceptability. Exploratory and confirmatory factor analysis (EFA/CFA), reliability (internal consistency, test-retest, inter-item and item-total correlations) and convergent validity were analysed for the intensity and interference dimensions of the questionnaire. A combined EFA with these two constructs supported a 2-factor structure distinguishing intensity (α = 0.88) from interference items (α = 0.91). CFA was tested for the interference dimension, demonstrating suitability for this sample. Item-total correlations were >0.30 on both dimensions and most inter-item correlations were <0.70. Test-retest reliability (n = 42) was good for intensity (r = 0.88) and interference (r = 0.73), and convergent validity was confirmed for most hypotheses (r>0.30).This questionnaire is a comprehensible tool, achieving a thorough assessment of relevant pain dimensions. The MHPQ can help guide treatment recommendations by highlighting relevant topics and contributing to more effective, integrated treatments.