Kinesiophobia in Rheumatoid Arthritis: Associations With Functional Disability, Disease Activity, and Related Clinical Factors

Rheumatoid arthritis (RA) is a chronic systemic inflammatory autoimmune disease affecting approximately 0.5-1% of the global population. It is characterized by persistent synovial inflammation leading to progressive cartilage and bone destruction, resulting in functional impairment and substantial physical, social, and psychological burden. Impairment of physical function and mobility is a core feature of RA, particularly in patients with high disease activity or advanced joint damage, where pain and inflammation directly limit movement and daily activities. However, reduced mobility in RA is not exclusively driven by inflammatory pathology. Increasing evidence suggests that non-inflammatory factors, including kinesiophobia, fatigue, depression, and anxiety, may significantly contribute to functional limitation. Kinesiophobia, defined as an excessive and irrational fear of movement related to pain or perceived risk of injury, constitutes a major challenge for patients with RA. This condition may initiate a self-perpetuating cycle in which movement avoidance leads to physical deconditioning, muscle weakness, and progressive functional decline. Such fear often arises from maladaptive interpretations of pain as a harmful sensory experience, resulting in avoidance behaviors and dysfunctional pain-related cognitions. In RA, altered pain-related cognitive processing and heightened fear responses appear particularly relevant, contributing to increased kinesiophobia as disease severity progresses. Importantly, elevated disease activity does not necessarily indicate the presence of kinesiophobia, as some patients may experience pain-related functional impairment in the absence of fear of movement. Conversely, kinesiophobia may develop in patients with low disease activity or minimal joint destruction, in whom fear itself-rather than active inflammation-becomes the principal driver of movement avoidance and disability. Several studies have demonstrated associations between kinesiophobia and disease activity, pain, fatigue, depressive symptoms, and anxiety in RA. These interrelated factors may reinforce fear-based avoidance behaviors that are not fully explained by objective inflammatory burden. Depression and fatigue are common non-inflammatory manifestations of RA and are closely linked to disease burden and functional impairment, further contributing to reduced physical activity. Anxiety is also highly prevalent in RA and has been identified as an important contributor to fear of movement, even among patients with relatively low disease activity. In addition, sarcopenia has emerged as a clinically relevant comorbidity in RA. Recognized as a distinct clinical entity in the ICD-10 since 2016 in accordance with the European Working Group on Sarcopenia in Older People )EWGSOP2( recommendations, sarcopenia is characterized by reduced muscle mass and strength with impaired physical performance. It may be primary (age-related), typically manifesting in individuals aged 70 years and older, or secondary to chronic inflammatory conditions such as RA. Its reported prevalence ranges from 3% to 24% depending on diagnostic criteria and increases with age, although it is increasingly recognized in younger patients with autoimmune diseases. In RA, sarcopenia affects approximately 20-30% of patients and is associated with greater disease severity and poorer functional outcomes. Collectively, these findings underscore kinesiophobia as a multidimensional, non-inflammatory factor interacting with inflammatory, psychological, and musculoskeletal components of RA. This highlights the importance of systematically assessing kinesiophobia to better understand functional outcomes and to inform comprehensive, rehabilitation-oriented management strategies. Methods: All patients will be subjected to: 1. Full history taking and clinical examination. 2. Disease activity: the disease activity will be evaluated by disease activity score 28 (DAS 28). 3. Kinesiophobia: The TSK-17 will be used as it represents the original validated version and has been culturally adapted and validated in Arabic populations. This questionnaire consists of 17 items. Each item is rated on a four-point Likert scale ranging from 1 (strongly disagree) to 4 (strongly agree). The total score is calculated after inversion of the scores of items 4, 8, 12 and 16 yielding a total score between 17 and 68, where higher scores reflect greater fear of movement-related pain. A score of 37 differentiates between high and low scores. The scale is simple to administer, does not require specialized training, and involves no additional cost. 4. Pain: pain severity will be measured using Visual Analogue Scale (VAS). 5. Fatigue: The Arabic version of Fatigue Severity Scale (FSS) will be used. FSS includes 9 items that evaluate fatigue severity in the past week. Each item is scored between 1 (strongly disagree) and 7 (strongly agree). The average score of the 9-items represents the FSS total score. Higher scores indicate more severity. 6. Depression: The Arabic version of 21-item Beck Depression Inventory (BDI) will be used to assess depressive symptoms. Each item is scored ranging from 0 to 3, then the total BDI score is calculated by summing the scores of all items. The total score will range from 0 to 63, with higher scores reflecting greater severity of depression. 7. Anxiety: The Arabic version of the Beck Anxiety Inventory (BAI) will be utilized to assess anxiety symptoms. It is self-report questionnaire consisting of 21 items with good validity and reliability. Each item is scored from 0 to 3 with calculating the total score by finding the sum of the 21 items. Score of (0-21) = low anxiety, Score of (22-35) = moderate anxiety and Score of (36 and above) = potentially concerning levels of anxiety. 8. Sarcopenia: Assessment of sarcopenia will be done using the Arabic version of the SARC-F questionnaire. The SARC-F includes questions on five items: strength, assistance in walking, rising from a chair, climbing stairs, and falls. Each item is scored from 0 to 2 points, with a total score of 10 points. Total scores ≥4 indicates sarcopenia. 9. Functional disability: The Arabic version of Health Assessment Questionnaire Disability Index (HAQ-DI) will be used. The HAQ-DI includes 8 domains (dressing and grooming, arising, eating, walking, hygiene, reach, grip, and activities) and 20-items were used measuring functional disability over the past week. Each item is scored between 0 (without difficulty) and 3 (unable to do). The highest sub-category score represents each domain score. The total HAQ-DI score is the average score of eight domains that ranges between 0 and 3. higher scores means more disability. 10. Physical activity: The Arabic version of The International Physical Activity Questionnaire - Short Form (IPAQ-SF) will be used to assess physical activity. IPAQ-SF is a widely used, 9-item self-report tool that measures activity levels in adults (15-69 years) across walking, moderate-intensity and vigorous-intensity activities, estimating MET-minutes per week for overall activity and sitting time.