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Background: Juvenile Behçet’s Disease (JBD) is an extremely rare chronic systemic vasculitis. While the impact of the disease on functional capacity and fatigue has been documented in adult populations [1,2], there is a profound lack of objective data regarding physical fitness, functional capasity and gait kinematics in the JBD population [3]. Due to its orphan status and low prevalence, the secondary musculoskeletal and biomechanical consequences of JBD during critical developmental stages remain largely unexplored.
Objectives: This study aimed to physical fitness parameters, functional performance and gait dynamics between JBD and healthy age-matched controls.
Methods: A cross-sectional study was conducted involving 26 participants: 8 adolescents diagnosed with JBD (Group 1) and 18 age-matched healthy controls (Group 2). Demographic data, medication history, and disease activity—measured via the Behçet’s Disease Current Activity Form (BDCAF)—were recorded. Physical fitness was assessed using the FitnessGram® Physical Activity Battery (Curl-up, Trunk Lift, Push-up, Back Saver and Reach, Progressive Aerobic Cardiovascular Endurance Run-PACER tests). Functional performance was evaluated via the 6-minute walk test (6MWT), the 10-Stair Climb Test (10SCT), the 10-Stair Climb-Descent Test (10SCDT) and 30-second sit to stand (30STST) test. Gait parameters were evaluated using the Digitsole Pro® Smart Insole System. The Mann-Whitney U test was used for statistical comparison.
Results: A total of 26 participants were included in the study. There were no significant demographic differences between the JBD group (n=8) and healthy controls (n=18) (p>0.05). The groups were well-matched in terms of median age (15.5 vs. 16.0 years; p=0.542), height (164.0 vs. 169.5 cm; p=0.285), and body weight (59.5 vs. 64.0 kg; p=0.364). The JBD group had a mean BDCAF score of 1.62, indicating active disease, with a diagnosis duration ranging from 6.5 months to 10 years. Regarding medical management, all patients were on a stable medication regimen, primarily consisting of Colchicine, with 43% receiving additional immunosuppressive or biological agents (Azathioprine, Adalimumab, Methotrexate, or Apremilast) to control systemic involvement. Regarding physical fitness, JBD patients completed significantly fewer push-ups (4.0 vs 10.0; p<0.001) and curl-ups (12.5 vs 21.0; p=0.002) and significantly lower performance in both PACER laps (13.5 vs 28.0; p<0.001). Functional performance were markedly reduced in JBD patients, evidenced by and 6MWT distance (550m vs 620m; p<0.001), slower in the 10SCDT (6.55s vs 5.25s; p<0.001) and 10SCT (2.85s vs 2.35s; p=0.003), with a profound deficit noted in the 30STST (13 vs 19.5 repetitions; p<0.001). Furthermore, gait analysis revealed a significantly lower velocity (p=0.004) and a prolonged stance phase (0.70s vs 0.58s; p<0.001) in the JBD group. All evualation results are presented in Table 1.
Conclusions: Patients with JBD exhibit significant impairments in core strength, functional performance, and mobility compared to healthy peers. The altered gait pattern (increased stance phase) suggests a cautious walking strategy likely due to reduced stability or fatigue. The observed functional deficits, combined with an altered, cautious gait pattern, point towards a sarkopenic phenotype emerging as early as adolescence. Since chronic inflammation is a known driver of muscle catabolism, early identification of these deficits is vital. These findings highlight the critical need for integrating structured exercise programs and physical therapy into the multidisciplinary management of JBD to to counteract early-stage sarcopenia, prevent long-term physical disability, and preserve functional independence in this rare disease population.
Comparison of Physical Fitness, Functional Capacity, and Gait Parameters Between JBD Patients and Healthy Controls
| Parameter | Group 1 (n=8)
| Group 2 (n=18)
| p-value |
|---|---|---|---|
| Push-up (reps ) | 4.0 (2.0 – 5.5) | 10.0 (8.0 – 13.0) | <0.001 * |
| Curl-up (reps ) | 12.5 (9.0 – 15.0) | 21.0 (17.0 – 28.0) | 0.002 * |
| Trunk Lift (cm ) | 21.0 (18.5 – 22.5) | 28.5 (24.0 – 33.0) | 0.005 * |
| Back Saver and Reach (cm ) | 28.5 (23.5 – 32.0) | 33.5 (29.0 – 37.0) | 0.104 |
| 10SCDT (sec ) | 6.55 (6.20 – 6.90) | 5.25 (4.80 – 5.60) | <0.001 * |
| 10SCT (sec ) | 2.85 (2.60 – 3.10) | 2.35 (2.20 – 2.45) | 0.003 * |
| 30STST (n ) | 13.0 (11.5 – 15.0) | 19.5 (17.5 – 22.5) | <0.001 * |
| 6MWT (meters ) | 550.0 (525 – 575) | 620.0 (600 – 655) | <0.001 * |
| PACER (laps ) | 13.5 (8.0 – 17.0) | 28.0 (21.0 – 35.0) | <0.001 * |
| Gait Velocity (m/s ) | 4.60 (4.20 – 4.75) | 5.45 (5.15 – 5.90) | 0.004 * |
| Stance Phase (s ) | 0.70 (0.68 – 0.73) | 0.58 (0.54 – 0.61) | <0.001 * |
| Swing Phase (s ) | 0.38 (0.35 – 0.40) | 0.44 (0.41 – 0.47) | 0.002 * |
| Cadence (steps/min ) | 110.0 (101 – 116) | 127.0 (120 – 142) | 0.012 * |
6MWT: 6-Minute Walking Test; 30STST: 30-Second Sit-to-Stand Test; 10SCT: 10-Stair Climb Test; 10SCDT: 10-Stair Climb-Descent Test; PACER: Progressive Aerobic Cardiovascular Endurance Run; BSRT: Back Saver Sit and Reach Test; IQR: Interquartile Range; Group 1: Juvenile Behçet’s Disease; Group 2: Healthy Controls.
REFERENCES: [1] Ilhan B, Can M, Alibaz-Oner F, et al. Fatigue in patients with Behçet’s syndrome: relationship with quality of life, depression, anxiety, disability and disease activity. Int J Rheum Dis 2018;21:2139-45.
[2] Moses Alder N, Fisher M, Yazici Y. Behçet’s syndrome patients have high levels of functional disability, fatigue and pain as measured by a Multi-dimensional Health Assessment Questionnaire (MDHAQ). Clin Exp Rheumatol 2008;26(4 Suppl 50):S110-3.
[3] Koné-Paut I. (2016). Behçet’s disease in children, an overview. Pediatric rheumatology online journal, 14(1), 10.
Acknowledgments: NIL.
Disclosure of Interests: None declared.