Central Pain Mechanisms and Clinical and Psychological Factors Associated With Pain Interference in Daily Life in Adults With Hemophilia and Hemophilic Arthropathy

Central Pain Mechanisms and Clinical and Psychological Factors Associated With Pain Interference in Daily Life in Adults With Hemophilia and Hemophilic Arthropathy: A Cross-Sectional Observational Study

Introduction. Chronic pain is a frequent complication in adults with hemophilia and hemophilic arthropathy that affects functionality and quality of life. In addition to joint damage, central pain mechanisms and psychological factors may contribute to its functional impact, although evidence in this population is limited.

Objective. To analyze the association between central pain mechanisms, pain intensity, and pain-related anxiety and pain interference in daily life in adults with hemophilia and hemophilic arthropathy, adjusting for relevant clinical variables.

Methods. An analytical observational study with a cross-sectional design will be conducted in 138 adults with hemophilia and hemophilic arthropathy. The dependent variable will be pain interference in daily life (Brief Pain Inventory), the main predictor variables will be central sensitization (Central Sensitization Inventory), conditioned pain modulation (Conditioned Pain Modulation Index), global pain intensity (severity subscale of the Brief Pain Inventory), and pain-related anxiety (Pain Anxiety Symptoms Scale-20). As secondary predictor variables, sleep quality (Pittsburgh Sleep Quality Index) and pain self-efficacy (Pain Self-Efficacy Questionnaire) will be included. As confounding variables, joint damage, age, type of treatment, and history of inhibitor will be considered. The association between variables will be analyzed using multiple linear regression models adjusted for relevant clinical covariates.

Expected results. It is expected to identify factors associated with pain interference in adults with hemophilia and hemophilic arthropathy, improving the understanding of its functional impact.

Inclusion Criteria:

• Diagnosis of hemophilia A or B
• Age equal to or greater than 35 years
• Clinical diagnosis of hemophilic arthropathy in at least one lower limb joint
• Clinically relevant joint involvement, defined as a total score on the Hemophilia Joint Health Score (HJHS) greater than 4 points
• Stable prophylactic treatment with FVIII/FIX concentrates or monoclonal antibodies
• Provision of written informed consent

Exclusion Criteria:

• Presence of neurological or cognitive impairments that prevent understanding of the questionnaires or performance of the study tests
• Episode of hemarthrosis in the lower limbs within the 3 months prior to assessment
• Use of analgesics, nonsteroidal anti-inflammatory drugs, opioids, or other medications with potential effects on pain perception or modulation within the 72 hours prior to assessment
• Receiving, at the time of the study, physiotherapy, infiltrative, or orthotic interventions aimed at pain or function of joints affected by hemophilic arthropathy