Evaluation of the Turkish version of the Bath Ankylosing Spondylitis Patient Global Score (BAS-G)

Test-retest reliability of outcome measures: data from three trials in radiographic and non-radiographic axial spondyloarthritis

Objectives

Aim of this study was to assess test–retest reliability of candidate instruments for the mandatory domains of the Assessment of Spondyloarthritis international Society (ASAS)-Outcome Measures in Rheumatology core set for axial spondyloarthritis (axSpA).

Methods

Screening and baseline data from COAST-V, COAST-X and RAPID-axSpA was used to evaluate test–retest reliability of each candidate instrument for the mandatory domains (disease activity, pain, morning stiffness, fatigue, physical function, overall functioning and health). A maximum time interval of 28 days between both visits was used for inclusion in this study. Test–retest reliability was assessed by intraclass correlation coefficient (ICC). Bland and Altman plots provided mean difference and 95% limits of agreement, which were used to calculate the smallest detectable change (SDC). Data were analysed for radiographic and non-radiographic axSpA separately.

Results

Good reliability was found for Ankylosing Spondylitis Disease Activity Score (ICC 0.79, SDC 0.6), C reactive protein (ICC 0.72–0.79, SDC 12.3–17.0), Bath Ankylosing Spondylitis Functional Index (ICC 0.87, SDC 1.1) and 36-item Short-Form Health Survey (ICC Physical Component Summary 0.81, SDC 4.7, Mental Component Summary 0.80, SDC 7.3). Moderate reliability was found for Bath Ankylosing Spondylitis Disease Activity Index (ICC 0.72, SDC 1.1), patient global assessment (ICC 0.58, SDC 1.5), total back pain (ICC 0.64, SDC 1.3), back pain at night (ICC 0.67, SDC 1.3), morning stiffness (ICC 0.52–0.63, SDC 1.5–2.2), fatigue (ICC 0.65, SDC 1.3) and ASAS-Health Index (ICC 0.74, SDC 2.5). Reliability and SDC for the radiographic and non-radiographic axSpA subgroups were similar.

Conclusion

Overall reliability was good, and comparable levels of reliability were found for patients with radiographic and non-radiographic axSpA, even though most instruments were developed for radiographic axSpA. Composite measures showed higher reliability than single-item measures in assessing disease activity in patients with axSpA.

Health-related quality of life in Moroccan patients with ankylosing spondylitis

The main objective of this study was to assess the aspects of health-related quality of life (QOL) in patients with ankylosing spondylitis (AS) and to explore the disease-related parameters influencing it. One hundred patients with AS according to New York Classification criteria were recruited in this cross-sectional study. The Medical Outcomes Study Short Form 36 Health Survey (SF-36) was used to assess health-related QOL. Assessment criteria included the evaluation of disease activity (Bath Ankylosing Spondylitis Disease Activity index [BASDAI]), global well-being (Bath Ankylosing Spondylitis Global Index [BASGI]), enthesitis (Mander enthesis index [MEI]), functional status (Bath Ankylosing Spondylitis Functional Index [BASFI]); metrology (Bath Ankylosing Spondylitis Metrology Index [BASMI]) and radiographic damage (Bath Ankylosing Spondylitis Radiologic Index [BASRI]). In this study, males comprised 67% of the subjects; mean age was 38 ± 13 years and mean disease duration was 9.5 ± 6.8 years. Among these patients, 52% had hip involvement. Our patients had a moderately active disease and severe functional disability. All domains of SF-36 were deteriorated with low scores. The SF-36 subgroups most affected were role limitation (18.8 ± 28.1), role emotional (19.4 ± 35), general health (44.9 ± 20.3) and vitality (38.0 ± 18.2). Lower scores of SF-36 had good statistically significant correlations with altered functional status (BASFI), worse general well-being (BASGI), altered metrology (BASMI); and moderate correlations with high disease activity (BASDAI), important radiological damage (BASRI); restricted chest expansion and prolonged morning stiffness (p < 0.001). This study states that health-related QOL in Moroccan patients with AS is damaged in a significant way. Mental as well as physical aspects were affected. Functional disability, patient's well-being, metrology and disease activity are the main factors associated with deteriorating domains of QOL in AS. Recognizing complicated relationships between clinical measures and QOL in patients with AS can help us to develop further management strategies to improve their QOL.