POS1505-HPR VALIDATION OF THE DANISH VERSION OF THE BRISTOL RHEUMATOID ARTHRITIS FATIGUE MULTI-DIMENSIONAL QUESTIONNAIRE (BRAF MDQ) AND THE BRISTOL RHEUMATOID ARTHRITIS FATIGUE NUMERICAL RATING SCALES (BRAF NRS V2) IN PATIENTS WITH SPONDYLOARTHRITIS
Authors: A. Damgaard, J. Primdahl, A. Bremander, E. Dures, E. Lindqvist, E. Mogard, H. Krarup, J. Graversgaard, K. Knak
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Severe fatigue is highly prevalent in people with inflammatory arthritis IA [1], and an important outcome clinically and in research. The BRAF MDQ and three BRAF NRS v2 (severity, importance, and coping) are valid and reliable disease-specific tools for measuring fatigue in patients with rheumatoid arthritis [2,3], but information is lacking for patients with spondyloarthritis (SpA). <h3>Objectives:</h3> To validate the Danish BRAF MDQ and BRAF NRS v2 in patients with SpA. <h3>Methods:</h3> Validation followed COSMIN guidelines. The BRAF MDQ was analysed for: a) Content validity using cognitive interviews, b) Structural validity using confirmatory factor analysis (CFA), c) Internal consistency using Chronbach's alpha (with &gt; 0.70 as acceptable), d) Measurement error and reliability including relative reliability using intraclass correlation coefficient (ICC) (with &gt; 0.70 as acceptable) and absolute reliability using Bland-Altman plots, and e) Construct validity using the predefined hypotheses in Table 1 (75% fulfilled hypotheses as acceptable). The BRAF NRS v2 were analysed for construct validity and reliability. To assess test-retest reliability, the survey was conducted twice by patients with minimum one hour in between measurements. To study construct validity, patients completed the RAND short form 36 questionnaire (SF-36, first version) vitality subscale, the Visual Analogue Scale (VAS)-fatigue, VAS-pain, VAS-global impact of the disease, Hospital Anxiety and Depression Scale (HADS), and the Health Assessment Questionnaire (HAQ). In December 2023, the survey was sent to 350 patients, from the Danish Hospital for Rheumatic Diseases, age ≥18 years and with a confirmed diagnosis of SpA. <h3>Results:</h3> 149/350 patients (43%) completed the survey (52% female, mean ± standard deviation, age 59.1 ± 13.4 years, disease duration 15.2 ± 13.1 years); and 106 (71%) completed the test-retest reliability survey of the BRAFs. a) Content validity: four women (age 22-75 years) and six men (age 33-74 years) found the questions easy to read and understand and relevant, even though some did not experience fatigue across all the BRAF MDQ sub-scales. b) Structural validity: the CFA showed that the assumed four factor structure of the BRAF MDQ was not an acceptable fit. Therefore, an explanatory factor analysis was performed, and identified five factors. c) Internal consistency: Cronbach's α was 0.94 for the BRAF-MDQ total and 0.78–0.94 for the four sub-scales. d) Measurement error and reliability: The relative reliability had an ICC of 0.96 for the total BRAF MDQ and 0.93, 0.93, 0.89 and 0.83 for the four subscales. BRAF-NRS three subscales had ICCs of 0.90, 0.88 and 0.70. Absolute reliability based on Bland-Altman plots showed no trends between the difference and the mean for the BRAF MDQ. The mean difference was −1.68 points for the total score of BRAF-MDQ and -0.17 points for the BRAF NRS. Limits of agreement were 6.59 and −9.96 for BRAF-MDQ, and 5.45 and -5.79 for the BRAF-NRS. Standard error of measurement (SEM) was 0.47 points and minimal detectable change (MDC) was 1.9 points for the BRAF MDQ. SEM was 0.45 points and MDC was 1.86 points for the BRAF NRS. e) Construct validity for the BRAFs: 75% of the hypotheses were fulfilled (Table 1). <h3>Conclusion:</h3> The Danish BRAF MDQ and NRS are valid and reliable and can be used to measure fatigue in patients with SpA. <h3>REFERENCES:</h3> [1] Overman et al: PMID: 26272057. [2] Primdahl et al: PMID: 33605192. [3] Hewlett et al: PMID: 29087507. <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>